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Étude et réalisation d`un système de rétro

1. TABLE OF CONTENTS 1 LIST OF FIGURES 5 LIST OF TABLES 9 LIST OF ALGORITHMS 11 CHAPITRE 1 INTRODUCTION 13 1 1 LES DOMAINES DE LA RECHERCHE 14 1 2 LES OBJECTIFS DE LA RECHERCHE 16 1 3 L ORGANISATION DE LA THESE 18 CHAPTER2 RELATED RESEARCH AREAS 21 2 1 GEOMETRIC MODELLING 21 2 2 DECLARATIVE MODELLING 24 2 2 1 General and dedicated declarative modellers 30 2 2 2 The declarative conception cycle 30 2 2 3 The iterative design process 32 2 2 4 Levels of abstraction and levels of detail 33 2 2 5 Declarative modelling by hierarchical decomposition 34 2 2 6 MultiCAD system architecture 37 2 3 FEATURE BASED MODELLING 40 2 4 REVERSE ENGINEERING 43 2 4 1 Reverse engineering in scene modelling 44 2 4 2 Reverse engineering and geometric modelling 47 2 4 3 Reverse engineering and feature based modelling 49 2 4 4 Reverse engineering and declarative modelling 52 2 5 DISCUSSION 54 2 Table of Contents CHAPTER3 THESIS PROPOSAL AND IMPLEMENTATION 57 3 1 INTEGRATION OF THE TWO MODELS 58 3 2 RECONSTRUCTION PHASE 60 3 3 EXTENDED DESIGN METHODOLOGY 61 3 4 RS MULTICAD SYSTEM ARCHITECTURE 62 3 4 1 Data and knowledge storage 65 3 4 2 The stratified representation 70 3 4 3 Scene modifications 72 3 4 4 The propagation policy 74 3 4 5 The resultant declarative description 75 3 5 RS MULTICAD PROTOTYPE 76 3 5
2. ae el eew wv Geometric Layer Geometric has geometry properties has geometry Geometric properties has geometry M kitchen bedroom D has geometry Geometric Geometric properties has geometry G eometric properties previous previous has geometry has geometry properties Geometric properties Geometric properties has geometry eometric properties Figure 3 10 A typical stratified representation The construction of the stratified representation is a top down process where the hierarchical decomposition is built based on the geometric information coming from the 72 Chapter 3 geometric model For every object a node is created on the geometric layer of the stratified representation As long as all nodes have been created the pure geometric properties lead to the hierarchical decomposition by creating interconnected nodes on the declarative layer of the representation In Figure 3 10 appears a typical stratified representation 3 4 3 Scene modifications The dynamic stratified model of RS MultiCAD allows the designer to perform geometric and topological modifications on the scene Golfinopoulos et al 06 As soon as the designer modifies the scene a special process starts Every designer modification must be checked according to the rule set for its validity and if so the stratified representation mus
3. Type force Les Node Abstract Node xen D Ys 0 Zw Hon M 1194 10 5468 0 0000 Figure 4 17 Object insertion In case the designer inserts two new objects the dining room and the roof as child of the object site the modifications are applied since the positions are available The result is illustrated in Figure 4 18 Experimental Results 111 MRS MultiCAD RS MultiCAD E D 2 6938 7 3873 0 0000 Figure 4 18 Further objects insertion Type bina c Parent rte 1 Lea Node Abehuci Node Chichen aux bung org budding I K Corcel e pum 10 2 6938 7 3873 0 0000 Figure 4 19 Insert an abstract object In case the designer inserts a new abstract object type building as child of the object site and defines that the objects dining room 18 roof 19 and office 17 will be children of the new inserted object the insertion is applied Figure 4 19 illustrates the insertion The result of the insertion of the abstract node is shown in Figure 4 20 112 Chapter 4 M RS MultiCAD 15071507150 Type buikhng 13 5567 14 5066 0 0000 Figure 4 20 The result of the insertion 4 2 1 5 Delete In case the designer deletes the abstract object the building 20 the system ignores the relations of the rule set and the m
4. Figure 4 52 Experimental results of manual reduction of the solution space 140 Chapter 4 4 4 Discussion RS MultiCAD system implements a knowledge based reverse engineering approach in order to transform a geometric model which is generated by MultiCAD system into declarative model RS MultiCAD system uses an intermediate model the stratified representation in order to semantically understand the selected scene The stratified representation works properly and captures the geometric and the declarative information of the selected scene effectively The control module of the RS MultiCAD system is responsible for the construction manipulation and update of the stratified representation The algorithm of the construction is effective and the stratified representation is built by a top down way based on the geometric information of the objects that constitute the selected scene The stratified representation is updated correctly whenever the design modifies the selected scene Besides the declarative and the geometric layer of the stratified representation absorb the designer modifications The propagation policy contributes in order the stratified representation to reflect the exact state of the scene Moreover the system maintains a rule set and an object set The rule set consists of the designer requirements in terms of relations properties geometric properties and characteristics The object set consists of the objects that
5. building_4 Eh bathroom 3 adjacent east kitchen 8 flat 11 ELA bathroom 3 adjacent west bedroom 10 flat 12 roof 15 Add Relation Delete Relation Figure 2 10 The working space of MultiCAD MultiCAD incorporates an object relational database Miaoulis 02 which consists of five logical inter connected databases e The scene database contains information describing the scene models internal declarative representation models relations between the composing objects et cetera e The multimedia database contains all types of documents related to the project geometric models geometric primitive shapes multimedia information et cetera 40 Chapter 2 e The knowledge base contains all the necessary information about entities type their properties along with their relations e The project database deals with data concerning planning financial and other special aspects of each project e The concept database Ravani et al 04 includes concepts representations The Scene database is configured following the Scene Conceptual Modelling Framework CMF Miaoulis et al 00 where the description of a scene contains entities such as e objects defined by their properties simple or generic ones a single object corresponds to the existence of a real 3D object with well defined characteristics and properties a generic object covers a group of simple objects with properties in common e three types of relations
6. Coke 0 0 0 t e Type 7 quil Length Qual W hi 15 D Tv Is Long 2 a Wx peu re Relations ON GeoPropertios OFF Figure 4 5 Move flat_7 to new position In case the designer moves the object kitchen_8 to the 7 11 0 position that causes a violation of the rule set and the modification is canceled The object kitchen_8 is spatially related with the objects bathroom_9 and bedroom 10 The system propagates the modification and calculates the new positions of the brothers of the object kitchen 8 The objects flat_7 and long building are updated with their new positions According to their new positions there are two relations flat 7 is adjacent over with roof 15 and long building is longer than wide which are violated and the modification is canceled The result is illustrated in Figure 4 6 Experimental Results 103 RS MultiCAD Yai 11 Zes 0 Figure 4 6 Violation of kitchen 8 move In case the designer moves the object kitchen 8 to a new position without taking into account the rule set that causes a move ignoring the rule set As soon as the new position of the object kitchen 8 is available and included in the site the new position becomes current position of the object Equal Host L Shorter Than bedroom 10 Figure 4 7 Move kitchen_8 to new position ignoring the rule set 104 Chapt
7. Constraint satisfaction techniques for the generation phase in declarative modelling Geometric Modeling Techniques Applications Systems and Tools Muhammad Sarfraz Eds Kluwer Academic Publishers Dordrecht Hardbound 20 pages 2004 Li RK A part feature recognition system for rotational parts International Journal of Computer Integrated Manufacturing 1988 1 9 1451 75 Li ge S Le mod lisation d clarative incr mentale Application a la conception urbaine Th se de doctorat Nantes Novembre 1996 Lina Yan Ping Wanga Cheng Tao Daib Ke Rong Reverse engineering in CAD model reconstruction of customized artificial joint Medical Engineering amp Physics 27 2005 189 156 Bibliography Little et al 98 Lucas et al 90 Lucas et al 95 Makris 05 Makris et al 03 Martin P and D 88 Martin P and D 88 Miaoulis 02 193 Little G Tuttle R Clark DER Corney J The Heriot Watt feature finder CIE 97 results Computer Aided Design 1998 30 13 99 1 6 Lucas M Martin D Martin P Plemenos D Le projet ExploFormes quelques pas vers la mod lisation de formes BIRGE no 67 pp 35 49 1990 Lucas M Desmontils Declarative Modellers Revue Internationale de CFAO et d Inforgaphie vol 10 6 pp 559 585 1995 Makris D Etude et r alisation d un syst me d claratif de mod lisation et de g n ration de
8. However the XMultiFormes project does not incorporates any database management system which means that the designer is obligated to execute the whole design process at once and can not store the most desired geometric solutions for further manipulation The lack of a database management system also affects the update on the relationships since the available relationships are hard coded obviously and inhibits the designer to work on different domain other than the architectural design of buildings The inclusion process of XMultiFormes provides to the designer the only ability to modify declaratively the scene by including a sub scene in the declarative description with an existence scene which makes the process inflexible for further modifications Besides the geometric to declarative representation process requires computation time and the quality of the new declarative description which is produced in each iterative cycle is not evaluated since Sellinger does not present any convergence of the geometric solutions Generally speaking the cooperative computer aided design paradigm CCAD was used by Sellinger as a framework for the integration of the two modellers This paradigm was 54 Chapter 2 originally developed to provide an interactive generative geometric modelling system with a cyclic design path and it is well adapted to the declarative modelling The CCAD paradigm is based on the assumption than the system can not create
9. L L Object B Shorter Than Object A D C L Ly J Wider Than Narrower Than X Object A Wider Than Object B Y N U WOW J an Object B Narrower Than Object A W D S C WW J Relations and Properties 167 Higher Than Lower Than X x Object A Lower Than Object B N U H A H B VIE Object B Higher Than Object A D H H Higher Than Long A Z Ha X Object A Higher Than Long Y H L J N U Pa D S Higher Than Wide Object A Higher Than Wide Y V H A Ww J N U ra 168 Appendix A Longer Than High Object A Longer Than High Y LH N U VS D S Longer Than Wide que AN Object A Longer Than Wide Y LW N U VE D S Wider Than High Object A Wider Than High WOoH Relations and Properties 169 Wider Than Long Object A Wider Than Long Y WL N U VE A 2 Properties Is Long Is Wide Is Tall Object A sLong ENO Low Mediun High a Object A Is Wide No Low Medium High S Object A Is Tall N0 Low Medium High 170 Appendix A Position X Is Position Y Is Position Z Is Length Is Width Is Height Is Where Xi Y Zi coordinates of the object i Li length of the object i Wi length of the object i Hi length of th
10. MultiCAD suit le cycle de conception d clarative qui se compose de trois phases fonctionnelles s quentielles la phase de description de la sc ne la phase de g n ration et la phase de compr hension de la sc ne En outre MultiCAD incorpore cinq type de bases de donn es reli es ensemble sous un sch ma logiques o entre elles la base de connaissance contient toutes les informations n cessaires sur le type d objets le type de relations et le type de propri t s que le syst me supporte MultiCAD fournit au concepteur la capacit de d crire la sc ne d sir e par d composition descendante de haut en bas diff rents niveaux de d tails et en indiquant les propri t s et les relations de la sc ne de mani re impr cise et incompl te La d composition descendante de haut en bas avec les relations et les propri t s fonctionnent comme contraintes pour que MultiCAD produise un ensemble de mod les g om triques alternatifs qui sont visualis s travers un modeleur g om trique Le syst me RS MultiCAD a t d velopp pour faire face notre hypoth se et est plac dans l architecture du syst me MultiCAD Le mod le g om trique qui est produit par 144 Chapitre 5 MultiCAD a t refond et enrichi du type et de la forme des objets qui constituent la sc ne Le mod le g om trique est exprim par la position et les dimensions de la bo te englobante des objets avec n importe quelles autres caract ris
11. le m canisme g n rateur de solutions produit un ensemble de solutions g om triques alternatives qui Introduction 15 v rifient les propri t s d finies Lucas et al 90 Lucas et al 95 Finalement la troisi me est la phase de compr hension de solution o les solutions g om triques sont visualis es par un modeleur g om trique Lucas et al 95 Plemenos 95 La mod lisation d clarative permet le processus de conception it ratif par l ex cution du cycle de conception d claratif et ensuite facilite le concepteur dans sa r valuation de la description initiale de sc ne Desmontils 95 Le but fondamental des cycles d ex cution successifs est que le syst me doit converger vers un ensemble de solutions g om triques alternatives qui sont plus fid les aux exigences du concepteur Le processus it ratif se termine lorsque le concepteur estime qu elle il a atteint le but escompt L architecture MultiCAD Miaoulis et al 96 Miaoulis et al 98 est une architecture des syst mes d information multim dia et intelligents pour la Conception Assist e par Ordinateur CAO lib r es de l inflexibilit g om trique qui met en application la mod lisation d clarative en acceptant une description de sc ne et en produisant un ensemble de solutions g om triques alternatives qui satisfont la description de sc ne elle m me Parmi d autres bases de donn es MultiCAD incorpore une base de donn es de con
12. End If End 2 Algorithm 3 2 Extract relations and properties The first collection class contains all valid relations of the node and the second incorporates all properties along with their values RS MultiCAD uses a recursive algorithm which is presented in Algorithm 3 2 in order to extract all relations and properties According to Algorithm 3 2 the system starts from the root node and uses a preorder way to traverse the decomposition tree Using preorder the system visits first of all the root node then the left sub tree and finally the right sub tree On every node of the declarative layer of the stratified representation the extraction module receives the geometric information of the object by following the has geometry label As the geometric data are known the extraction module applies all stored properties in order to find out the current valid values 84 Chapter 3 Begin End COMPUTE SPATIAL RELATIONS objectnode node ES objectnode temp node While temp previous null temp temp previous End While While temp next null If node temp CALCULATE SPATIAL RELATIONS node geometry temp geometry temp temp next End While If node temp CALCULATE_SPATIAL_RELATIONS node geometry temp geometry End If x Algorithm 3 3 Compute the spatial relations The property types and their values are added to the property collection of the specific node The system p
13. L int gration des deux mod les d claratif et g om trique a lieu par l introduction d une nouvelle phase la phase de reconstruction dans le cycle de conception d claratif L architecture du syst me propos et la repr sentation dynamique de la m moire sont pr sent es Par ailleurs une s rie de modifications de sc ne est d finie et une politique de propagation suivie par le syst me propos afin d absorber ou de ne pas absorber des modifications de sc ne est esquiss e La politique de propagation est utilis e apr s une modification de sc ne afin que le syst me mette correctement jour la repr sentation intelligente La sous section suivante d crit la construction de la description d clarative r sultante qui sera transmise la phase de description d clarative dans l it ration MultiCAD suivante De plus la sous section suivante est consacr e la mise en oeuvre et pr sente les algorithmes principaux que le prototype propos incorpore De tels algorithmes concernent la construction de la repr sentation de la m moire dynamique la manipulation des modifications de sc ne ainsi que la construction de la description d clarative r sultante En conclusion la derni re sous section illustre les conditions du r alisateur pour le choix du modeleur g om trique classique d une part et d autre part pr sente les caract ristiques principales du modeleur g om trique classique choisi Le chapitre 4 pr sente l
14. and the relations properties are extracted Figure 4 32 illustrates the import of the external geometric model The initial rule set is empty since there is no declarative description 4 3 1 2 Object rename and type selection The objects that are imported from the external geometric model are recognized as of type unknown The designer can define their type by selecting the object and declaring their type from the type combo box Besides the name of the object can be renamed by clicking on the object name and typing the new name that the designer prefers The names of the objects become site kitchen bedroom office living room dining room bedroom vcorridor and hcorridor respectively Figure 4 33 illustrates the type declaration and the rename of the objects Kram MEE eium ee eo 9X iw 99 ne Shorter Than olhee EquilHeight b ngeoom Shore Than ivingeoom Nx 11 4507 6 1791 0 0000 Figure 4 33 Type declaration and object rename Experimental Results 125 4 3 1 3 Insert In case the designer inserts a new abstract object type house as child of the object site and defines that the rest objects will be children of the new inserted object the insertion is applied Figure 4 34 illustrates the insertion RS MultiCAD e 2 X Figure 4 35 Insert an object of type roof 126 Chapter 4 The designer inserts a new object of
15. clarative de sc ne r sultante en utilisant deux options alternatives la manuelle et la mani re automatis e La description d clarative de sc ne r sultante est constitu e des relations et des propri t s qui appartiennent l ensemble de r gles ainsi qu l ensemble d objets avec les relations fait partie de qui constituent l arbre de d composition hi rarchique RS MultiCAD manuel laisse le concepteur modifier seul l ensemble de r gles en ajoutant de nouvelles relations propri t s et ou en effa ant relations propri t s existantes qui appartiennent l ensemble de r gles et l ensemble d objets en fonction des conditions ult rieures La mani re automatis e permet au concepteur d effectuer toutes les modifications exig es comme cela se produit dans la mani re manuelle mais qui plus est RS MultiCAD ajoute les propri t s g om triques des objets appropri s l ensemble de r gles de la description d clarative de sc ne r sultante 5 1 Remarques de conclusion Le syst me RS MultiCAD agit dans les directions principales suivantes e La sc ne est comprise s mantiquement Le syst me RS MultiCAD re oit un mod le g om trique et afin de produire une nouvelle description de sc ne d clarative il construit un mod le interm diaire qui contient des informations g om triques et d claratives sur les objets qui constituent la sc ne choisie En particulier l information d clarative de la sc ne me
16. set node as children of father node node children convert_list_tree node If father next not null node father next CONVERT_LIST_TREE node Else Return End If Else If node next not null node node next CONVERT_LIST_TREE node Else Return End If End If End If End M P Algorithm 3 1 Convert a linked list into a decomposition tree 3 5 3 Extraction of relations and properties As soon as RS MultiCAD has constructed the stratified representation the next step is to extract all valid relations and properties which are accrued by applying all relation and property types of the knowledge database Every node of the declarative layer of the stratified representation embodies two collection classes Thesis Proposal and Implementation 83 EXTRACTION objectnode node Begin If node children null Then CALCULATE_PROPERTIES node children CALCULATE_REFLECTIVE_RELATIONS node children EXTRACTION node children If node next null Then COMPUTE_SPATIAL_RELATIONS node CALCULATE_PROPERTIES node next geometry CALCULATE_REFLECTIVE_RELATIONS node next geometry EXTRACTION node next Else COMPUTE_SPATIAL_RELATIONS node Return End If Else If node next null COMPUTE_SPATIAL_RELATIONS node CALCULATE_PROPERTIES node next geometry CALCULATE_REFLECTIVE_RELATIONS node next geometry EXTRACTION node next Else If node next null COMPUTE_SPATIAL_RELATIONS node Return Else Return
17. trique en 3D et un processus de haut niveau bas sur la connaissance pour la compr hension s mantique de la sc ne L approche bas e sur la connaissance d passe les m thodes d extraction par des caract ristiques puisqu elle est employ e pour extraire des rapports et des propri t s partir d un mod le g om trique donn et pour saisir l information g om trique et non g om trique dans le m me sch ma de repr sentation intelligente Le processus de conception d clarative produit un ensemble de mod les g om triques alternatifs qui sont bas s sur un mod le d claratif et abstrait Dans la m thode de mod lisation d clarative la r tro conception pourrait jouer un r le significatif et sera adapt e afin de transformer un mod le g om trique en mod le plus abstrait le mod le d claratif La motivation de cette recherche doit combiner la m thode de mod lisation d clarative telle qu elle est appliqu e dans l architecture MultiCAD avec la m thodologie de r tro conception afin de fournir une compr hension s mantique des mod les g om triques qui sont produits partir de l architecture du syst me MultiCAD Le processus de r tro conception de haut niveau est une approche s mantique qui saisit l information g om trique et non g om trique toutes deux extraites de la repr sentation g om trique en appliquant la connaissance de domaine sp cifique dans la m me repr sentation intelligente La base de c
18. 1 Geometric representation 76 3 5 2 The construction of the stratified representation 79 3 5 3 Extraction of relations and properties 82 3 5 4 The propagation policy 85 3 5 5 Scene modifications 86 3 5 5 1 Move operation 86 3 5 5 2 Scale resize operation 88 3 5 5 3 Insert operation 90 3 5 5 4 Deletion operation 91 3 5 5 5 Extra geometric characteristics operation 91 3 5 6 The resultant declarative description 9 CHAPTER4 EXPERIMENTAL RESULTS 95 4 1 RS MULTICAD ENVIRONMENT 95 4 1 1 Select mode 98 4 2 CASE I INTERNAL MULTICAD GEOMETRIC MODEL 98 4 2 1 Scene modifications 100 4 2 1 1 Object rename 100 4 2 1 2 Move 100 4 2 1 3 Scale Resize 105 4 2 1 4 Insert 110 4 2 1 5 Delete 112 4 2 1 6 Change extra geometric characteristics 113 4 2 1 7 Change the rule set 113 4 2 2 Model storage 116 4 2 2 1 Save the declarative description 116 4 2 2 2 Save the geometric solution 117 Table of Contents 3 4 2 3 Reduction of the solution space 117 4 2 3 1 Automated way 118 4 2 3 2 Manual way 120 4 3 CASE II EXTERNAL GEOMETRIC MODEL 122 4 3 1 Scene modifications 123 4 3 1 1 Import geometric model 123 4 3 1 2 Object rename and type selection 124 4 3 1 3 Insert 125 4 3 1 4 Change the geometric characteristics 126 4 3 1 5 Delete 126 4 3 1 6 Change the rule set 127 4 3 1 7 Move 129 4 3 1 8 Scale Resize 131 4 3 2 Model storage 134 4 3 2 1 Save the declarative desc
19. 3 2 The declarative properties Thesis Proposal and Implementation 69 Reflexive Relation Description Longer Than High O If O length is greater that O height the relation is TRUE otherwise is FALSE Longer Than Wide O If O length is greater that O width the relation is TRUE otherwise 1s FALSE Higher Than Long O If O height is greater that O length the relation is TRUE otherwise is FALSE Higher Than Wide O If O height is greater that O width the relation is TRUE otherwise is FALSE Wider Than High O If O width is greater that O height the relation is TRUE otherwise is FALSE Wider Than Long O If O width is greater that O length the relation is TRUE otherwise 1s FALSE Table 3 3 The reflective relations Pure Geometric Property Description Position X Is Oj The property equals to the X axis value of O bounding box Position Y Is O The property equals to the Y axis value of O bounding box Position Z Is O The property equals to the Z axis value of O bounding box Length Is O The property equals to the length of O bounding box Width Is O The property equals to the width of O bounding box Height Is O The property equals to the height of O bounding box Table 3 4 The pure geometric properties 70 Chapter 3 3 4 2 The stratified repr
20. A geometric solution can be stored in the Multimedia Database of MultiCAD but also can be stored in DXF format The geometric solution is related to the respective declarative description The shapes of the objects along with the dimensions of the bounding boxes and any extra geometric characteristics that may have any object of the scene are stored Figure 4 28 shows the respective records that are stored 38 vevtest2_2 MultiCAD Edito 39 vastest2 3 MultiCAD Edito 40 vostest 4 MultiCAD Edito 42 vas paper vassilis 44 vas paper MultiCAD Edito D 45 vas_paperd MultiCAD Edito 45 final vanoilis 47 finDXF MultiCAD Edito 45 fin vas vansilis salution Table sohtionid scene id 1H823338888 gTSSR2J233ESSETDEOI2IJSEESETZBE AP 40 4B 4D 4B 4B 48 48 480 s 46 48 48 48 4B EJ 48 4n 4 an 93 94 sec 8 CT Dolo ies Figure 4 48 Save the geometric solution 136 Chapter 4 4 3 3 Reduction of the solution space The reduction of the solution space can be achieved by two alternative ways that are supported by the RS MultiCAD system the automated and the manual way 4 3 3 1 Automated way The first iteration of MultiCAD produces a set of alternative geometric solutions by supplying only the geometric properties of the object site In the second iteration the declarative description is provided additionally with the geometric properties of the next level of detail In other words the
21. Detailed system architecture of RS MultiCAD system 21 28 29 29 31 22 33 36 36 39 42 45 47 58 59 60 61 62 64 6 List of Figures Figure 3 7 The inner operation cycle of RS MultiCAD 65 Figure 3 8 The ER diagram of data and knowledge storage 66 Figure 3 9 The basic structure 70 Figure 3 10 A typical stratified representation 71 Figure 3 11 The propagation policy 74 Figure 3 12 The generalization factor 75 Figure 3 13 The roof morphology 77 Figure 3 14 Control points of B Spline curves 78 Figure 3 15 A typical linked list of the declarative layer 79 Figure 3 16 A tree of two decomposition levels 80 Figure 3 17 The decomposition tree 81 Figure 3 18 The calculation of spatial relations 84 Figure 3 19 The IDEF3 diagram of the propagation policy 86 Figure 4 1 The working space of RS MultiCAD 96 Figure 4 2 The stratified representation of Case I 99 Figure 4 3 Move long_building to new position 100 Figure 4 4 Move kitchen_8 to new position 100 Figure 4 5 Move flat_7 to new position 102 Figure 4 6 Violation of kitchen_8 move 103 Figure 4 7 Move kitchen_8 to new position ignoring the rule set 103 Figure 4 8 Position not available 104 Figure 4 9 Move long building 105 Figure 4 10 Resize bathroom 9 106 List of Figures Figure 4 11 Resize flat_7 to a new length Figure 4 12 Violation
22. GecPropesties OFF Figure 4 8 Position not available In case the designer moves the object long_building to a new position that is next to high building object the relation long_building adjacent north high building emerges Experimental Results 105 File Scene Change Reban Options coc om Ol ETES 2557255 255 Figure 4 9 Move long_building In that case if the designer adds the new relation to the rule set and moves long building next to aux building that causes a move of the high building object as well The result is illustrated in Figure 4 9 4 2 1 3 Scale Resize In case the designer resizes the object bathroom 9 to a new length equals to 2 the modification is applied The object bathroom 9 is adjacent west to the object kitchen 8 and adjacent east to the object bedroom 10 according to the rule set Changing the length of the object bathroom 9 the modification is propagated to its brothers The modification does not affect the object kitchen 9 which remains in the same position but affects the object bedroom 10 which moves to a new position The ancestors of the object bathroom 9 are updated accordingly The result is illustrated in Figure 4 10 In case the designer resizes the object flat 7 to a new length equals to 7 the changes are propagated to all children of the object flat 7 None of relations and properties which belon
23. Miaoulis 02 In the majority of cases we start from an initial idea and arrive to details stage by stage The levels of detail represent the hierarchical top down or bottom up approach of the design process In the framework of the declarative modelling the levels of detail are represented on the decomposition tree of the declarative description The evolutionary character of the design process is traced by the axis of time the levels of abstraction and the levels of detail Miaoulis et al 00 The design process is defined as a succession of similar stages for reaching the final model and can be represented as a spiral in a three dimensional space An initial idea serves as a starting point As time evolves the level of detail increases while the level of abstraction decreases until the achievement of the final model Figure 2 7 illustrates the evolution of the design process 2 2 5 Declarative modelling by hierarchical decomposition A special approach of the declarative modelling is declarative modelling by hierarchical decomposition Plemenos 91 which gives the user the ability to describe a scene by top down decomposition at different levels of detail The objective of this method is to remedy the disadvantages of the traditional geometric modelling by allowing the description of a scene by its properties which can be imprecise and incomplete More accurately the declarative modelling makes possible to indicate the properties which veri
24. Th se Universit de Limoges France 2001 Sagerer G Niewmann H Semantic networks for understanding scenes Plenum Press N York 1997 Sanchez S Le Roux O Luga H Gaildrat V Constraint Based 3D Object Layout using a Genetic Algorithm 31A 2003 International Conference Limoges France 2003 Schumaker L Triangulations in Computer Aided Geometric Design IEEE Computer Graphics and Applications 1993 13 1 45 52 Sellinger D Perspectives on the integration of geometric and declarative models for scene generation Rapport de recherch MSI Universit de Limoges France 1995 Sellinger D Plemenos D Interactive generative geometric modeling by geometric to declarative representation conversion WSCG 97 pp 504 513 Plzen Czech Republic February 1997 Sellinger D Le mod lisation g om trique d clarative interactive Le couplage d un modeleur d claratif et d un modeleur classique Th se Universit de Limoges France 1998 Simon H A The Science of the Artificial MIT Press Cambridge MA USA 1996 Siret D Propositions pour une approche d clarative des 160 Bibliography Sonthi et al 98 Stamati et al 05 Thompson et al 99 V rady 91 Varady et al 97 Vassilas et al 02 Vergeest et al 05 ambiances dans le projet architectural Application a l ensoleillement Th se de doctorat Nantes Fran
25. and feature based modelling In the feature modelling field object semantics are semantically represented for a specific application domain In other words a semantic feature is an application oriented feature defined on geometric elements There are three approaches for building a feature model e the design by feature approach creates the feature model of an object by composing the available features in a feature library e the feature recognition approach recognizes various features from a geometric model of an object according to the feature templates defined in a feature library e the feature conversion approach enables the definition of other feature models based on a feature model of a product already created The new feature model corresponds to alternative views of the same product Feature conversion is a technique that defines the basis for multiple view feature modelling systems Bronsvoort 01 In order to create a feature model of an object from a point cloud the embedded features must be recognized These features are then used to constrain the fitting process Feature recognition methodologies can be classified into two major categories surface recognition and volume recognition The main difference between these two categories is 50 Chapter 2 mainly due to the feature definition and object description in the recognition method The features and object description in the surface recognition category are expres
26. as modules responsible for introducing architectural knowledge Ravani et al 03 representation of architectural styles Makris et al 03 collaborative design Golfinopoulos et al 04 and intelligent user profile Plemenos et al 02 Bardis et al 04 Bardis et al 05 The main disadvantages of the constraint satisfaction programming search strategy is the exhaustive search which leads to unacceptably long times in relatively large problem spaces the inability to interact with the designer and derive solutions that satisfy the designer aesthetics Makris 05 proposes a generation engine based on generic algorithms and handles with limitations the latter disadvantage while Bonnefoi et al 02 deals with the first disadvantage The directions of MultiCAD software architecture framework are defined through a research project supported by the Laboratory XLIM of the University of Limoges along with the Intelligent Information Systems Engineering Team of Informatics Department of TEI Technological Education Institute of Athens MultiCAD is a multi layered architecture that comprises the following main layers Miaoulis 02 e The interface layer incorporates functions such as intelligent visualisation of scene models and documents creation and editing of models and description formulation of the request traditional formulations of SQL spatial SQL or free text search navigation and browsing of databases acquisition and editing t
27. between objects meronymic relations which are used to describe physically or conceptually part of relations is part of is included in spatial organization relations which are used to specify the relationships between objects near by on left higher than and reflective relations which are used to describe comparisons of the same object higher that large higher than deep e and properties that characterise and describe the objects is_tall high colour green et cetera The generated scene solutions are visualised through their geometrical representation Bitmaps Miaoulis 02 VRML Vassilas et al 02 and AutoCAD designs Makris et al 03 The designer can evaluate the solutions according to his her criteria either by selecting the best ones or by setting a score to each of them Vassilas et al 02 2 3 Feature based modelling Feature based modelling is used for modelling products the last years One of its main advantages over the geometric modelling is the ability to associate functional and engineering information to shape information in a product model The basic entity of a feature model is Related Research Areas 41 the feature defined as a representation of shape aspects of a product that are mappable to a generic shape and are functionally significant for some product life cycle phase In general feature model is the elementary part of the pro
28. continues by calling itself recursively with the next brother of the node The algorithm traverses the whole tree and adds only the pure geometric properties of the nodes whose depth is less than the generalization factor which has been specified by the designer At this point it must be pointed out that if the generalization factor is less than the maximum tree depth then nodes with depth less than the generalization factor and without descendants are not allowed to add their pure geometric properties to the rule set The main reason is based on the fact that the addition of the pure geometric properties of leaf nodes to the rule set will lead MultiCAD to generate geometric solutions with no diversity at these points since nodes inherit their topological position on the scene from their children Unlike if the generalization factor equals to tree depth then the pure geometric properties of all nodes are added to the rule set leading MultiCAD to produce only one geometric solution in the next iteration Chapter 4 Experimental Results The objective of this chapter is to present the experimental results that come out of the underlined functionality of RS MultiCAD system In the first sub section a brief user guide of the RS MultiCAD working environment is presented and in the second and third sub section two different case studies are illustrated The choice of the case studies is based on two main reasons The first reason is the origina
29. desirable scene in terms of properties of the components of the scene and produce a set of alternative geometric solutions that meet the designer requirements which have been already specified by the designer in the scene declarative description phase The modes of generation are various such as constrain satisfaction genetic algorithms etc e Understanding tools are tools that allow visualization selection and comprehension of the geometric solutions These tools may incorporate mechanisms for representing realistic images exploring the solution space etc 2 2 3 The iterative design process The design process in declarative modelling is iterative Each cycle consists of executing the phases of description generation understanding and then the designer has to reconsider the initial description After the execution of successive cycles the system must converge towards a set of alternative geometric solutions that are closer to the designer requirements The process stops when the designer estimates that has achieved the goal Go Gi G D Description g G Generation lt M Do S Solutions Pa U Understanding e U M Modifications Uo Figure 2 6 The iterative design process Related Research Areas 33 The iterative process can be represented by a spiral where in each successive iteration a set of geometric solutions are produced from a scene description which has been modified in order the so
30. embodies the designer modifications That resultant declarative description leads to more promising solutions and reduces the initial solution space Keywords Declarative modelling Reverse engineering Knowledge based systems Computer aided design Discipline Informatique Universit de Limoges Laboratoire XLIM 83 rue d Isle 87000 LIMOGES FRANCE
31. friendly and facilitates the designer to perform modifications on a selected scene by providing dialog boxes A future graphical support on designer modifications should enforce the user friendliness of the system Chapitre 5 Conclusions et perspectives Cette th se a pr sent l hypoth se suivante la possibilit de transformer un mod le g om trique en un mod le d claratif dans le cadre de la mod lisation d clarative pendant la premi re phase du processus de conception Afin de confronter l hypoth se une approche de r tro conception bas e sur la connaissance a t d velopp e et est responsable pour le couplage d un modeleur g om trique classique avec un modeleur d claratif L approche se place dans le cadre de la mod lisation d clarative et de la r tro conception de haut niveau ayant comme objectif principal la mise en valeur et l exploitation de la connaissance du domaine d application qui est accumul e dans un syst me de conception d clarative du type MultiCAD pour que soit possible d un c t la compr hension s mantique de la sc ne mod le g om trique par le syst me et d un autre c t les traitements post rieurs du mod le d claratif cons cutif abstraite par le concepteur en tenant compte de la dimension s mantique de la sc ne MultiCAD Miaoulis 02 est un cadre d architecture de logiciel qui met en application la mod lisation d clarative par d composition hi rarchique Plemenos 91
32. geometric properties of the object house_10 are provided by RS MultiCAD to the declarative description MultiCAD produces a set of alternative solutions that meet the designer requirements and the additional pure geometric properties of the declarative description When the generalization factor is set to maximum tree depth there is only one solution that meets the rule set indeed Generalization Factor No Solutions 1 61072 2 80 3 1 Table 4 10 Automated reduction of the solution space The exact numbers of solutions per generalization factor are illustrated in Table 4 10 Figure 4 49 presents some solutions generated by the automated way The experimental results of all possible iterations of the specific example are illustrated in Figure 4 50 where the z axis of the chart is in logarithmic scale Experimental Results 137 Figure 4 49 Geometric solutions generated by the automated way 100000 10000 1000 100 4 No Solutions Generalization Factor Figure 4 50 Experimental results of automated reduction of the solution space 4 3 3 2 Manual way During the reduction of the solution space by the manual way the designer has the ability to change the relative rule set by adding or removing relations and properties from the rule set In the second step the designer adds the relation hcorridor adjacent south living 138 Chapter 4 room t
33. in order to be able to process another specific modelling area PolyFormes and VoluFormes are some of the dedicated declarative modellers 2 2 2 The declarative conception cycle Generally speaking the operation of a declarative modeller is based on declarative conception cycle which is cut out in three phases more or less sequential Lucas et al 95 Desmontils 95 Colin et al 97 The scene description phase A declarative modeller starts with the description of the desired scene The designer describes how he perceives the scene by specifying properties Related Research Areas 31 of the scene or leaving them ambiguous Declarative modellers use description languages close to the natural language while others use graphical user interfaces allowing designers to declare the structure of the desired scene Finally a transformation takes place translating the description of the scene into a model called internal declarative model e The generation phase The scene generator inputs the internal declarative model and produces a set of solutions that meet the description of the desired scene The capacities of the generator characterize completely the declarative modeller since this phase is the heart of the modeller The effectiveness of the modeller depends on the speed of treatment of input data and its extensibility and flexibility deals with the capacity to integrate new parameters of description whereas it is already in
34. is based on interactive modelling Sellinger s approach is traditional cooperative and gives a special emphasis on man machine interaction since it gathers all relevant information form the designer in order to convert a geometric into declarative model There is room for further improvement by exploiting domain specific knowledge and using an object oriented approach which facilitates the designer to manipulate a selected Related Research Areas 55 scene states his her requirements either in geometric or declarative way during the iterative design process and after a few iterations the designer gathers all promising geometric solutions Thus we concentrate on settling the high level reverse engineering in declarative modelling framework The knowledge based reverse engineering approach is presented in Chapter 3 Chapter 3 Thesis proposal and implementation The objective of this chapter is to present a deep overview of the thesis proposal and implementation The main hypothesis of this thesis 1s to integrate the two models the declarative and geometric The integration takes place in a new defined phase in the declarative conception cycle the reconstruction phase RS MultiCAD has been designed in order to handle the integration of the MultiCAD declarative modeller with a traditional geometric modeller RS MultiCAD implements the knowledge based reverse engineering approach in order to transform a geometric solution which has be
35. is created the respective arrows of the nodes that constitute the detail level are redefined to point to the appropriate nodes When both transition operators are not applicable to none node of a level of detail then the process backtracks to some node of a higher level of detail and the process goes on a different direction The process stops when both transition operators are not applicable and all nodes have been processed Figure 3 17 shows the decomposition tree after the process has been completed Algorithm 3 1 illustrates the main core of the operation that converts a linked list into a decomposition tree At this point it must be pointed out that the algorithm is effective and all computations are quick The algorithm has been tested with more than forty objects and it effectively operates on constructing the declarative decomposition tree and updating all respective arrow labels appropriately Thereby the intermediate model is appropriately constructed so it will be 82 Chapter 3 enriched with semantic knowledge by exploiting the knowledge base and it will be correctly updated whenever the designer applies modifications on the scene CONVERT_LIST_TREE objectnode node Begin If node has_geometry is_part_of other node has_geometry Then If node next not null Then node node next CONVERT_LIST_TREE node Else Return End If Else father node If node has_geometry consists_of other node has_geometry Then
36. modelling the description phase evaluates the scene description for coherence and the generation phase incorporates a resolution engine which has been implemented within the GNU Prolog environment and deals with the constraints resolution on finite domains 2 2 6 MultiCAD system architecture MultiCAD Miaoulis et al 96 Miaoulis et al 98 is a proposed multimedia CAD system liberated of geometric inflexibility which will be used for the creation of scenes MultiCAD is a software architecture framework for the development of multimedia and intelligent information systems in order to support declarative design processes Miaoulis 02 The MultiCAD system is based on the declarative modelling of scenes by hierarchical decomposition The objective of this method is to remedy the disadvantages of the traditional geometric modelling by allowing the description of a scene by its properties which can be imprecise and incomplete Lucas et al 90 Plemenos 91 Plemenos 95 More accurately the declarative modelling makes possible to indicate the properties which verify the desirable scene in several levels of detail allowing thus a top down design 38 Chapter 2 The design environment of MultiCAD features a rich set of modules These include alternative modules for solution generation using constraint satisfaction programming Bonnefoi et al 02 Plemenos et al 97 or genetic algorithms Vassilas et al 02 Makris 05 as well
37. moves the object living room to the position 4 4 0 which is occupied by another object and without taking into consideration the rule set the modification is canceled since the modification is not propagating to the rest of brothers The result is illustrated in Figure 4 41 4 3 1 8 Scale Resize In case the designer resizes the object kitchen to a new length equals to 4 5 the modification is applied The modification is propagated in a circular way affecting all brothers According to the rule set the new length dimension of the object kitchen affects the position of the object bathroom which in turn affects the position of the objects office and hcorridor The object office in turn affects the position of the object living room which in turn affects the position the object bedroom Besides the position alters of the objects dining room and vcorridor The ancestors of the object kitchen are updated accordingly The result is illustrated in Figure 4 42 MRS MuttiCAD eaux SL 3 7960 10 3402 0 0000 Relations ON GeoPropertion OFF Figure 4 42 Resize kitchen to a new length In case the designer resizes the object kitchen to a new width equals to 3 5 all brothers move to new positions in the same way as the above example The result is illustrated in Figure 4 43 132 Chapter 4 RS MultiCAD iw 9 eme Figur
38. or models based on semantic networks e Intermediate models They are primarily geometric models These models are concrete from the point of view of the geometric properties of objects of their composition and of their of space arrangement Geometrical models can produce several different models of the lower level of abstraction if for example differ the properties of appearance such as the color or texture of the objects e Physical models The models of the physical level contain information appropriate to the direct visualization of the 3D objects that constitute the scene They contain all necessary object properties in order to represent real situations Abstract models Li Geometric models L Physical models J Figure 2 12 The transformation of models Miaoulis 02 introduces the notion of vertical transformation of the levels of abstraction An abstract model is transformed or generates a set of concrete models in terms of more concretion and less ambiguity The reverse process of the generation is the comprehension where a physical model is transformed into geometric and abstract model with less concretion and more ambiguity Figure 2 12 illustrates the transformation of the models The comprehension process is actually the reverse engineering within the framework of the design process 46 Chapter 2 Reverse engineering is an important branch of the design process and has been widely recognized as a crucia
39. perfect geometric solutions but superior designs can be generated by allowing the designer to guide the system through successive rounds 2 5 Discussion Engineering is involved in designing manufacturing constructing and maintaining of products systems models and structures At a higher level there are two types of engineering forward engineering and reverse engineering Forward engineering is the traditional process of moving from high level abstractions and logical designs to the physical implementation of a system or product Reverse engineering can be viewed as the process of analyzing a system model in order to identify the sub components and their interrelationships create representations of the system model in another form or a higher level of abstraction and reengineer the physical representation of that system model In designing reverse engineering process permits the transformation of one model into another one In the framework of geometric modelling reverse engineering is used in order to construct a 3D model from a physical model Furthermore reverse engineering in feature based modelling is used in order to extract features from feature instances of the geometric model In declarative modelling approach reverse engineering is used to transform the geometric model into a declarative model Sellinger s thesis presents a first attempt of coupling a traditional geometric modeller with a declarative modeller and
40. peuvent tre principalement manufactur s L objectif de la conception d taill e est de d velopper l efficacit la plus lev e possible de tous les composants mod les afin de produire des sch mas n cessaires des d tails techniques des caract ristiques et des tol rances qui permettront au mod le d tre fabriqu 14 Chapitre 1 Le processus de conception architectural Simon 96 se concentre sur la d finition d taill e d un mod le spatial de mani re permettre sa r alisation mat rielle Pour tout produit ou syst me architectural le processus de conception d bute par la conception conceptuelle dont le but est de produire un mod le ou la repr sentation d une entit qui sera plus tard construite Le processus traite de la combinaison de l intuition et du jugement bas s sur l exp rience acquise par la construction de mod les semblables De plus le processus traite d un ensemble de principes dans le cadre duquel le mod le volue d un ensemble de crit res qui permet la qualit d tre jug e et d un processus d it ration qui m ne une repr sentation de conception finale 1 1 Les domaines de la recherche La mod lisation d clarative Lucas et al 90 est une m thode de mod lisation alternative qui adapte le processus de conception surmonte les inconv nients de la mod lisation g om trique et permet au concepteur de d crire la sc ne d sir e en d finissant ses propri t s qui p
41. that the object kitchen must be adjacent west to object bathroom and adjacent south to object dining room the object bathroom must be adjacent west to object office and adjacent south to object hcorridor the object living room must be adjacent north to object office and adjacent east to object bedroom and finally the object dining room must be adjacent south to object bedroom and adjacent west to object vcorridor Finally the designer specifies that all objects have the same height Figure 4 38 illustrates the spatial relations that belong to the rule set Figure 4 38 Spatial relations Experimental Results 129 4 3 1 7 Move In case the designer moves the object kitchen to a new position that causes a move to all brothers The same result will appear if the designer moves the object house_10 to a new position As soon as the new position of the object kitchen is available and included in the site the new position becomes current position of the object RS MultiCAD propagates the modification to the object dining room and bathroom and updates their new positions The object dining room in turn propagates the modification to the object vcorridor and bedroom The object bathroom in turn propagates the modification to the object hcorridor and office Finally the object bedroom prop
42. type of every node as unknown type As the time that the linked list has been created RS MultiCAD activates a specialized process in order to convert the linked list into the decomposition tree based on the geometric information of the respective nodes The specialized process applies two transition operators e The consists of transition operator which determines if an object O consists of another object O The comparison is based on the position and the dimensions of the bounding box of the two objects In other words if the bounding box of the object O includes the bounding box of the object Oj then the consists of transition operator is applicable and the object O becomes parent of the object Oj e The is part of transition operator which determines if an object O is part of another object O The comparison is based again on the position and the dimensions of the bounding box of the two objects In other words if the bounding box of the object O is included in the bounding box of the object O then the is part of transition operator is applicable the object O becomes child of the object Oj PARENT Object3 EK D CHILDREN 5 bi he ee gi m PARENT PARENT PARENT PARENT PARENT PREV Object Object2 Object4 Object5 Object6 Object7 PREV lt n PREV PREV EK NEXT ux NEXT ic vex ond CHILDREN CHILDREN CHILDREN CHILDREN CHILDR
43. used to reduce the dimensionality of the reconstruction parameter space A sequential numerical constrainment process is used which allowed them to detect and automatically reject inconsistent constraints A nice alternative to fitting tangential and blend surfaces was to parameterize swept 2D features with the cross section of the inter surface join blend as the 2D feature A special branch of reverse engineering is the reverse design where in Vergeest et al 05 during the reverse design of free form shapes existing shapes or features can be extracted 52 Chapter 2 and be inserted into a model or otherwise reused for the creation of a new design Here it is essential to note that the existing features might not be designed as such but are perceived as an entity by the designer In addition the designer might expect that the feature possesses parameters that he she can control whereas such parameters were never defined An important aspect of reverse design is therefore the interactive assignment of complex controls to shapes or features These controls are needed by the designer to achieve shape modifications which could be very situation dependent The interactive assignment can be dependent on or expressed in terms of for example characteristic points or curves in the shape under construction or in any other existing shape This referring to features which were not designed as such is one form of reverse design 2 4 4 Rever
44. 3 9 presents the basic structure schematically PARENT Geometric Propetries HAS GEOMETRY Object T CHILDREN PREV NEXT Figure 3 9 The basic structure Every node corresponds to an object and every arrow label indicates the relations of the node The labels denote the following meanings Thesis Proposal and Implementation 71 The parent and children labels which connect nodes with same level of abstraction different level of detail and represent the meronymic relations The next and previous labels which connect nodes with the same level of abstraction and the same level of detail The has geometry label which connects nodes of different level of abstraction and represents the geometry of an object The has topology label which connects nodes of the same level of abstraction indicating the topological relations among objects and represents the reflective and spatial relations The has property label is related to a node in order to indicate that the object has the specific property Declarative Layer site nit low 1 1 Iac d a cm children parent parent building garage next TE children parent parent previous n it low ao el ew roof flat re previous iw low children parent parent parent f Q3
45. 5 is tall no Table 4 6 Additional Properties 33 RS MultiCAD 10 7477 12 2218 0 0000 EN Are you sure you ware to change the status of the relation Figure 4 23 Rule set enhancement 116 Chapter 4 4 2 2 Model storage 4 2 2 1 Save the declarative description As soon as the designer has completed all modifications he she saves the new declarative description in the Scene Database of MultiC AD The declarative description uses four interconnected tables The dm_ scene table contains information about the stored scenes such as scene id scene description et cetera The dm object table contains the decomposition tree of each stored declarative description where the part of relations are stored The object relations table contains all relevant spatial and reflective relations of the declarative description and finally the object property table incorporates all properties which have been declared by the designer Figure 4 24 shows a typical example of a stored declarative description 1 a house of sartorini dimitris makris 10 vassilist vassilis 11 vassilis2_dm vassilis 12 vassilis3 vassilis 13 vassiliss vassilis 1 EME vassilis 17 GogTest BasiliZ 24 LOGTestScane Baz 26 MultiCAD Editor Sco MultiCAD Eto Record OT Tv ot zs 230 aux building 238 long building 240 high building 241 Imng room 5 242 play room amp 243 roof 13 244 roofl 4 245 04 7 246 roof 15 247 kitc
46. 60 Chapter 3 3 2 Reconstruction phase The declarative conception cycle of MultiCAD system architecture see section 2 2 6 can be extended to an iterative process by using a reconstruction phase Golfinopoulos et al 05 where the scene is semantically understood and refined by adding more detailed descriptions in successive rounds of declarative design process In this case undesirable designs are cut from the set of solutions the size of the solution set after each round of generation can be reduced and after a few iterations the designer gathers all promising solutions Under the reconstruction phase an intermediate model is built in order to handle all the necessary information concerning the declarative and geometric side of the scene The aim of the reconstruction phase is to receive a geometric model provide a new declarative model enhanced with geometric constraints to the scene declarative phase and also permit the designer to change the geometry of the scene by modifying the geometric aspects of the objects These changes are semantically checked and the intermediate model is updated Generation Selection extends uses Designer Data amp uc Solution Kon torage Understanding a les p uses E ate i extends ux extends A Scene Description Figure 3 3 The new declarative conception cycle Figure 3 3 presents the new declarative conception cycle by placing the new reconstruction phase in a UML u
47. 8 Chapter 3 In case the designer takes into consideration the rule set the general bounding box that will be moved is not only the bounding box of the selected object but also the bounding boxes of all related objects of the selected object and furthermore the related objects of the related objects and so on recursively as the rule set indicates On the other hand in case the designer does not take into consideration the rule set the general bounding box is identical with the bounding box of the selected object ignoring the rule set Two main checks are executed in order to be clear whether the new position of the general bounding box is inside the scene and is not occupied by another object that is not enmeshed with the move operation The control module applies the propagation policy and whereas the relations and properties that belong to the rule set are still valid the new state is legalised The next step is to recalculate the relations and properties of the nodes of the declarative layer The new relations and properties are added to the collection classes respectively If there is a violation then stratified representation backtracks to the old state and the control module activates the explanation module 3 5 5 2 Scale resize operation The scale operation aims to change the dimensions of the object relatively while the resize operation changes the dimensions of the object according to the designer requirement The scale and res
48. E otherwise is FALSE 68 Chapter 3 Adjacent_East O Oj If O is adjacent east to Oj the relation is TRUE otherwise is FALSE Adjacent Over O Oj If O is adjacent over to Oj the relation is TRUE otherwise is FALSE Adjacent Under O O If O is adjacent under to Oj the relation is TRUE otherwise is FALSE Equal Lenght O Oj If O length equals to O length the relation is TRUE otherwise is FALSE Equal Width O Oj If O width equals to O width the relation is TRUE otherwise is FALSE Equal Height O O If O height equals to O height the relation is TRUE otherwise is FALSE Longer Than O Oj Shorter Than O Oj Wider Than O O Narrower Than O Oj If O length is greater less than O length the relation is TRUE otherwise is FALSE If O width is greater less than O width the relation is TRUE otherwise is FALSE Higher Than Oj Oj Lower Than O Oj If O height is greater less than O height the relation is TRUE otherwise is FALSE Table 3 1 The spatial relations Declarative Property Description Is Long O Is Wide O Is Tall O Every property is defined within a range of a maximum and minimum value according to the domain The range of values is divided into portions and the property can be set into declarative values e g Low Medium High Table
49. EN CHILDREN Figure 3 16 A tree of two decomposition levels The two transition operators are applied on every node of the linked list and when there is node where the is part of transition operator is not applicable with any other node and the consists of transition operator is applicable with all other nodes of the linked list then it becomes parent of the rest nodes In other words the algorithm tries to find out which object bounding box includes all rest objects bounding boxes and simultaneously the former Thesis Proposal and Implementation 81 object bounding box is not included in none other objects bounding boxes Figure 3 16 illustrates how the linked list becomes a tree of two levels of detail PARENT Object3 ee NEN P CHILDREN qu m PARENT Object Object7 VE PERV te al cd vex emn Ns cmn Ns d P udi PARENT PARENT L PARENT PREV Object2 Object4 Object5 Object6 PREV ae SE PREV ar PREV f md A nex CHILDREN CHILDREN CHILDREN CHILDREN Figure 3 17 The decomposition tree The construction of the decomposition tree is based on the depth first search and the process continues recursively for every node as any of the transition operators is applicable For every level of detail that
50. Figure 4 15 ewm es eo vq iwi pieno Verger Than High Wide Then th ea Wider Then Long 1917 10 4187 0 0000 Relations OFF GeoPropesties OFF Figure 4 15 Scale aux_building In case the designer scales the object living room_S by 10 the modification is canceled since position is occupied by another object because there is none relation in the rule set for objects living room_5 and play room_6 The result is presented in Figure 4 16 gene miam eoe ow v iwi Scale Resize Relations OFF GeoProperties OFF Figure 4 16 Position not available 110 Chapter 4 4 2 1 4 Insert In case the designer inserts a new object he she has first of all to define the object type the position that will occupy the inserted object along with the dimensions of the object Finally the designer has to specify the parent object of the inserted object Figure 4 17 illustrates the corresponding window that gathers all relevant information for object insertion The designer inserts a new object of type office with position at 7 0 0 and length width height equal to 2 3 2 respectively The parent of the new object is the object site The system examines whether the position is available and included in the site and if so creates the new object and updates the declarative panel along with the graphical display accordingly Eram IG
51. Figure 4 37 The deletion of the object roof_11 127 Figure 4 38 Spatial relations 128 Figure 4 39 Move object kitchen 129 Figure 4 40 Move the object office ignoring the rule set 130 Figure 4 41 Position not available 130 Figure 4 42 Resize kitchen to a new length 131 Figure 4 43 Resize kitchen to a new width 132 Figure 4 44 Position not available 132 Figure 4 45 Resize vcorridor to a new length 133 Figure 4 46 Violation of scaling the house 10 134 Figure 4 47 Save the declarative description 134 Figure 4 48 Save the geometric solution 135 Figure 4 49 Geometric solutions generated by the automated way 137 Figure 4 50 Experimental results of automated reduction of the solution space 137 Figure 4 51 Geometric solutions generated by the manual way 139 Figure 4 52 Experimental results of manual reduction of the solution space 139 Figure B 1 The DXF file of a 3D box 173 Figure C 1 The object model of VectorDraw 177 List of Tables Table 3 1 The spatial relations Table 3 2 The declarative properties Table 3 3 The reflective relations Table 3 4 The pure geometric properties Table 4 1 Spatial Relations Case I Table 4 2 Reflective Relations Case I Table 4 3 Properties Case I Table 4 4 Additional Reflective Relations Case I Table 4 5 Additional Spatial Relations Case I Table 4 6 Additional Properties Case I Table 4 7 Automated reduction of t
52. Les repr sentations classiques sont incapables de saisir et de manipuler l information g om trique et non g om trique sous la m me forme leurs natures tant diff rentes L intelligence artificielle et les approches orient es objet fournissent une repr sentation 18 Chapitre 1 sp cialis e afin de saisir et g rer correctement l information g om trique et non g om trique sous la m me repr sentation e Surmonter les probl mes relatifs aux modifications effectu es par le concepteur sur la sc ne D s que le concepteur a choisi un mod le g om trique d sir elle il a la capacit d effectuer les modifications qui changent la g om trie des objets qui constituent la sc ne et ou qui affectent la topologie de la sc ne Toutes les modifications doivent tre v rifi es en fonctions des exigences initiales du concepteur et doivent tre galement prises en consid ration pour le mod le d claratif r sultant e Surmonter les probl mes d importation des mod les g om triques construits par un autre modeleur g om trique classique MultiCAD produit les mod les g om triques qui bien qu ils contiennent l information g om trique ils contiennent galement le type d objets qui constituent la sc ne L approche bas e sur la connaissance de r tro conception supporte galement l importation des mod les g om triques construits par un autre modeleur g om trique classique en fournissant les quipements n cess
53. M Solution Geometric Model Generation Visualization Generation Phase Solution Understanding Phase Figure 3 4 Extended design methodology and modelling levels Initially the object set consists of all objects of different level of abstraction and the rule set consists of all relations properties that the designer has declared during the declarative description phase Based on that rule set a set of geometrical solutions is produced by a solution generator The solutions are visualized through a 3D viewer and the designer selects the most desirable solution which can be edited The reconstruction phase is implemented through the RS MultiCAD system which receives the selected scene and converts into a stratified representation The rule set and the 62 Chapter 3 object set can be edited by adding deleting and changing the objects relations and properties of the scene The designer can proclaim his requirements declaratively and geometrically during the reconstruction phase new declarative description is constructed which contains the changes and a new MultiCAD cycle starts resulting in more promising solutions The iterative process aims to produce scenes which meet the requirements after refinement Figure 3 4 presents the extended design methodology and the modelling levels 3 4 RS MultiCAD system architecture The high level architecture of the proposed RS MultiCAD system can be seen as th
54. Solutions 1 Initial Set 182988 Initial Set 2 76636 long building adjacent north high building Initial Set 3 long building adjacent north high building 38318 aux building adjacent north long building Initial Set long building adjacent north high building aux building adjacent north long building 4 24990 high building position X20 high building position Yz0 high building position Z 0 Table 4 8 Manual reduction of the solution space 200000 160000 120000 80000 No Solutions 40000 Step Figure 4 29 Experimental results of manual reduction of the solution space 122 Chapter 4 Step 2 Step 3 z Step 4 v w vo e Figure 4 30 Geometric solutions generated by the manual way 4 3 Case II External geometric model The example of Case II is based on an external geometric model that has been created by a commercial geometrical modeler The designer draws a 3D box which represents the site and afterwards places inside the initial box eight other 3D boxes which represent a layout of rooms Figure 4 31 illustrates the design Experimental Results 123 L VectorCAD example 1 GE Fie General Edt View Insert Draw Format Modfy Window Help Ax DEN RAS BS BVP POD BW ouo xo r1 fea vdDocument SNIN Property Vale 4 s w n I X 2 w actives STANDARD e Qo ActiveFil k Color n elt Biz A
55. UNIVERSIT DE LIMOGES COLE DOCTORALE Science Technologie Sant FACULT des Sciences et Techniques Laboratoire XLIM Th se N 24 2006 Th se pour obtenir le grade de DOCTEUR DE L UNIVERSIT DE LIMOGES Discipline Informatique pr sent e et soutenue publiquement par Vassilios S GOLFINOPOULOS le 21 Juin 2006 Etude et r alisation d un syst me de r tro conception bas sur la connaissance pour la mod lisation d clarative de sc nes Th se dirig e par Professeur Dimitri PL M NOS Co encadrement Professeur Georges MIAOULIS JURY Pr sident M le Professeur Djamchid GHAZANFARPOUR Universit de Limoges Rapporteurs M le Professeur Marc DANIEL cole Sup rieure d Ing nieurs de Luminy M le Professeur G rard H GRON cole d Architecture de Nantes Examinateurs M le Professeur Georges MIAOULIS TEI d Ath nes M le Professeur Dimitri PLEMENOS Universit de Limoges Remerciements Je tiens t moigner ma plus profonde reconnaissance mon directeur de recherche Monsieur le Professeur Dimitri PL M NOS de l Universit de Limoges qui a dirig ce travail et qui m a conseill et encourag avec une constante bienveillance J aimerais galement le remercier pour m avoir donn la possibilit de r aliser un de mes v ux les plus chers Je remercie Monsieur Georges MIAOULIS Professeur d Informatique de l Etablissement d Enseignement Technologique d Ath nes T E I pour avo
56. a Greca et al 06 a declarative approach of parametric surface modelling is presented which is based on B Spline and NURBS representation The designer gives to the system a description set of geometric topological or physical properties The object shape is designed by manipulating several control points and the result is a set of parametric surfaces corresponding to the user requirements 2 2 1 General and dedicated declarative modellers There are two families of declarative modellers one can meet according to the treated field The general purpose modellers cover a large set of possible applications imply generality and consider as open since they are domain independent The solution generation engine can process several kinds of general properties trying to cover different domains and incorporating extendable capabilities On the other hand general purpose modellers suffer from their lack of efficiency because of the generality of the solution generation mechanism Plemenos et al 02 MultiFormes and Dem ons are some of the general purpose declarative modellers The dedicated modellers whose field of application is very precise The main advantage of the dedicated modellers is a significant precise vocabulary since the domain is almost closed and their efficiency because their solution generation engine can be well adapted to the properties of the specific domain On the other hand it is difficult for such a modeller to evolve
57. a direct connection with the knowledge database of the MultiCAD Additionally the knowledge database incorporates three tables the Object Type Relation Type and the Property Type table The knowledge database includes all object types relation types and property types which are supported by the system All object types are defined along with their primitive shape in the Object Type table The relation types are described through mathematical formulas in the Relation Type table The mathematical formula is expressed through geometric parameters from the Geometric Parameter table Finally the property types are defined within a range of a maximum and minimum value according to the domain in the Property Type table The object property value corresponds to a declarative value which accrues from the subdivision of the range values into portions The knowledge database consists of all relation and property types which are supported by the system The spatial relations declarative properties reflective relations and pure geometric properties are presented in Table 3 1 3 2 3 3 and 3 4 see Appendix A Spatial Relation Description Adjacent North O Oj If O is adjacent north to O the relation is TRUE otherwise is FALSE Adjacent South O Oj If O is adjacent south to Oj the relation is TRUE otherwise is FALSE Adjacent West O Oj If O is adjacent west to Oj the relation is TRU
58. agates the modification to the object living room and the system updates the positions of all objects Besides the modification is propagating to the ancestors of the object kitchen In other words the system updates the object house 10 with its new position The result is illustrated in Figure 4 39 Fie Scene Change Rein Options 7 eiim esie 2 0 vw eut eene v e T house 10 Current Shton 0 UT f z NL x Lenge Than Wide EL Lu 0363 14 5548 0 0000 Relstions ON GecPropesties OFF Figure 4 39 Move object kitchen In case the designer moves the object office to a new position without taking into account the relations of the rule set the modification is not propagated to other brothers 130 Chapter 4 MRS MultiCAD fev fc Fie Scene Charge Return Options eism ee ew ewi9 9e 250 25 240 Type office Wider Than batheoom Shot Than hengeoom Nowower Than ngecom Equs Widh dringroom EqusMeid dringroon Longer han dringroon Figure 4 40 Move the object office ignoring the rule set The system updates the object office along with the object house 10 with their new positions The result is illustrated in Figure 4 40 Longer Than High Wider Than High Longer Than Wide Relations OFF GeoPropertes OFF Figure 4 41 Position not available Experimental Results 131 In case the designer
59. aires pour recueillir toute l information appropri e au concepteur De cette fa on le concepteur a la capacit de continuer les manipulations de modifier la sc ne et d inclure la sc ne dans le cycle conceptuel d claratif 1 3 L organisation de la th se Le chapitre 2 illustre les domaines de recherches principaux de cette th se le cadre de mod lisation d clarative le cycle de conception d claratif ainsi que le processus it ratif de conception de la mod lisation d clarative sont pr sent s Une br ve vue d ensemble des repr sentations g om triques de base est pr sent e avec les avantages et les inconv nients de la mod lisation g om trique En outre on pr sente la m thode de r tro conception qui permet la transformation d un mod le en un mod le de niveau d abstraction plus lev Le chapitre propose une br ve r vision de la reconstruction 3D qui pr sente le processus de bas niveau du r tro conception en mod lisation En outre la r tro conception dans la mod lisation par les caract ristiques est esquiss e afin d accentuer le champ d identification du dispositif La derni re sous section pr sente que la r tro conception dans l approche de la Introduction 19 mod lisation d clarative qui est employ e pour transformer un mod le g om trique choisi en un mod le de niveau d abstraction plus lev le mod le d claratif Le chapitre 3 illustre la proposition et la r alisation de la th se
60. ale The exact numbers of solutions per generalization factor are illustrated in Table 4 7 Figure 4 28 presents some solutions generated by the automated way Generalization Factor N Solutions 1 182988 2 630 3 490 4 1 Table 4 7 Automated reduction of the solution space 120 Chapter 4 ws Ve fe 1a Figure 4 28 Geometric solutions generated by the automated way 4 2 3 2 Manual way During the reduction of the solution space by the manual way the designer has the ability to change the relative rule set by adding or removing relations and properties from the rule set In the second step the designer adds the relation long_building adjacent north high_building to the rule set that result to a reduced solution space according to the solution space of step 1 The designer continues to add relations and properties and finally in step 4 apart from the relations he adds geometric properties of the object high_building that lead to further reduction of the solution space The experimental results of manual reduction of the solution space of the specific example are illustrated in Figure 4 29 where the z axis of the chart is in logarithmic scale The exact numbers of solutions per step are illustrated in Table 4 8 Figure 4 30 presents some geometric solutions generated by the manual way according to the steps of Table 4 8 Experimental Results 121 Step Rule Set No
61. ar or rectangular patches have been reported earlier Farin 82 However such problems are avoided using triangular patches as more complex topologies can be modelled with triangles rather than with rectangles However triangular or rectangular patches are not the only ones available for modelling purposes There have also been n sided patches and smoothing techniques based on them reported in the literature Charrot et al 84 Varady 91 The current CAD applications are based on parametric tools and need all relevant information to create the desired object which means that do not offer any assistance at the conception itself since the designer should know all the details of the object to be created before calling upon the CAD system A CAD system in order to overleap this disadvantage should deal with the lack of information on the non geometrical aspects of the object the lack of levels of abstraction and the possibility to input imprecise description Geometric models are collections of components with well defined geometry and often interconnections between components Foley at al 99 One of the problems is to give an accurate geometrical representation to an object Primitives must be used for modelling an object The primitives are often selected dependent on the specific object and the level of accuracy required 24 Chapter 2 Practically traditional geometric modelling is generally applied to well defined simple objec
62. aracteristics MultiCAD geometric model also contains the object types The object type indicates the primitive geometric shape which is used in order to represent the respective object The objects are expressed by two main primitive geometric shapes the parallelepiped and the roof shape Thesis Proposal and Implementation 77 The first primitive is a simple geometric shape the parallelepiped which is represented by its position and basic dimensions The position of the parallelepiped is an array of the X Y and Z axis value of the 3D coordinate system The basic dimensions of the parallelepiped form an array of the length width and height as well The parallelepiped is used in order to represent object of types bedroom kitchen living room bathroom et cetera The second primitive is a complex geometric shape which is used in order to represent the object of type roof The object of type roof has been modelled based on the approach which has described in Makris 05 The roof primitive geometric shape is represented through the position of the bounding box its basic dimensions along with extra geometric characteristics The extra geometric characteristics are the appropriate parameters which are used in order to construct and manipulate the respective primitive geometric shape D Offset Length i SPLines 5 SPLine 6 SPLines 7 SPLine 4 SPLines 3 SPLine 2 Figure 3 13 The roof mo
63. arall l pip de ferm qui est constitu par six surfaces de B zier reli es Le syst me RS MultiCAD emploie le mod le g om trique qui a t produit par MultiCAD et qui contient toutes les informations n cessaires sur la g om trie des objets qui constituent la sc ne mais qui contient galement des informations suppl mentaires sur la forme et le type d objets Chaque objet est exprim en termes de position et les dimensions de base de sa boite englobante avec n importe quelles caract ristiques g om triques suppl mentaires qui d crivent l objet Le syst me RS MultiCAD construit un mod le interm diaire afin de saisir l information g om trique et d clarative Le mod le stratifi est caract ris par sa flexibilit manipuler et absorber les modifications du concepteur Le syst me XMultiForms emploie un syst me marquant afin de maintenir l information d clarative et g om trique dans la m me structure Dans le syst me XMultiFormes le concepteur a la capacit de changer la sc ne g om triquement la diff rence du syst me RS MultiCAD qui fournit les modifications g om triques et d claratives de sc ne Dans le syst me XMultiFormes l int gration du modeleur d claratif et g om trique est claire mais ne pas int gr e dans un processus it ratif de mod lisation d clarative D autre part RS MultiCAD facilite et introduit la notion du processus it ratif support e par ordinateur de mod lisation
64. are summarized in Chivate et al 95 Petitjean et al 02 In conventional reverse engineering processes 1D point cloud data or 2D range images sampling data of the surface of interest is acquired by digitizing devices CMM laser scanner etc or photographing devices CCD camera ICT MRI etc respectively Reverse engineering methods diverges from data measuring strategies Commonly used data acquiring devices can be categorized into contact or non contact devices Contact type devices are generally more accurate but slow in data acquisition and vice versa for non contact type devices According to whether the probe is held by operators contact devices can be further divided into two classes automatic devices and manually holding devices The common drawback of contact devices is that they may deform or even damage the surface of the object being digitized because of the direct physical contact Non contact devices measure the point coordinates using distance measuring methods such as laser scanner and sonar The 48 Chapter 2 merit of non contact distance measuring methods is high scanning speed The accuracy of this type of digitizers is dependant on surface reflectance the light paths to the sensor and the material transparent or semitransparent et cetera In engineering areas such as aerospace automotives shipbuilding and medicine it is difficult to create a CAD model of an existing product that has a free form
65. ated Research Areas 29 description is translated in an internal model made of linear constraints The generation engine of Demons uses a linear constraint solver called Oranos able to process dynamic constraints new constraints can be added during generation and hierarchical constraints Hierarchical constraints are constraints with priorities assigned by the user Whenever there is no solution for a given description constraints with low priority are released in order to always get a solution In Sanchez et al 03 another approach is presenting which applies a generic algorithm to the constraint solver Complex scenes are produced from basic and complex sets of constraints combined with Boolean trees Le Roux et al 04 presents a generic constraint solver based on classical constraint satisfaction techniques and a declarative modeller for virtual 3D environements called DEM ONS NG Figure 2 3 presents scenes created by Demons Figure 2 3 Scenes created by Dem ons BatiMan In Champciaux 98 a declarative modeller is illustrated which deals with the architectural construction of buildings and introduces an incremental training for solution reduction since the generation of solutions is very time consuming process and the visualisation of all solutions is unrealistic Figure 2 4 presents a building created by BatiMan Figure 2 4 Examples of generated buildings by BatiMan 30 Chapter 2 In La Greca et al 04 and L
66. can be considerable variation in performance and function required for this kind of products and it is therefore essential to involve the customer in the design process e The virtual environment to build the virtual reality environment in which the overall design of a product can be evaluated quickly and effectively Reverse engineering and modelling techniques can be combined into tools as meant from the current literature Figure 2 13 presents the correspondence between the type of models and the levels of abstraction Declarative models are characterised as the most abstract models since none geometric information is included Feature models consist of both geometric and feature based information Related Research Areas 47 Declarative models Feature models Geometric models D E Physical models Levels of Abstraction X XE Figure 2 13 Models according to the level of abstraction 2 4 2 Reverse engineering and geometric modelling The 3D reconstruction is a huge field and of course there is a vast literature on the specific subject The input of reverse engineering process is the physical object of interest while the output is its CAD model either a surface representation or a volume representation The conversion between surface and volume model can be done by mature algorithms such as voxelization and marching cube algorithms Surface representations and fitting methods for reverse engineering
67. ce Conception assist e par ordinateur Title Study and implementation of a knowledge based reverse engineering system for declarative scene modelling Abstract Declarative modelling allows the designer to describe a scene without the need to define the geometric properties by specifying its properties which can be imprecise and incomplete Declarative modelling by hierarchical decomposition 1s a special approach which gives the user the ability to describe a scene by top down decomposition at different levels of detail The MultiCAD system architecture implements the declarative modelling by hierarchical decomposition accepting a declarative description generating a set of geometric solutions that meet the description and visualizing the solutions through a geometric modeller The aim of the present work is to settle the reverse engineering process through the RS MultiCAD system which is a knowledge based system in order to couple a declarative with a traditional geometric modeller The declarative conception cycle of declarative modelling is extended in order to include the reverse engineering process by introducing the reconstruction phase and the iterative design process becomes automated During the reconstruction phase RS MultiCAD receives a selected geometric solution which is semantically understood permits the designer to perform geometric and topological modifications on the scene and results a declarative description which
68. ce Juin 1997 Sonthi R Gadh R MMCs and PPCs as constructs of curvature regions form feature determination Computer Aided Design 1998 30 13 997 1001 Stamati Vasiliki Fudos Ioannis A parametric feature based CAD system for reproducing traditional pierced jewellery Computer Aided Design 37 2005 431 449 Thompson WB Owen JC de St Germain HJ Stark SR Henderson TC Feature based reverse engineering of mechanical parts IEEE Trans Robot Automat 1999 15 1 57 66 Varady T Overlap patches a new scheme for interpolating curve networks with n sided patches Computer Aided Geometric Design 1991 8 7 27 Varady T Martin R Cox J Reverse engineering of geometric models an introduction Comput Aided Des 1997 29 4 255 68 Vassilas N Miaoulis G Chronopoulos D Konstantinidis E Ravani I Makris D Plemenos D MultiCAD GA A System for the design of 3D forms based on genetic algorithms and human evaluation SETN 02 Conference LNAI 2308 Springer Verlag 2002 pp 203 214 Vergeest J S M Bronsvoort W F Towards reverse design of freeform shapes WSCG 2005 Plzen Czech Republic Bibliography 161 Wang et al 03 Woodward 87 Zhang 03 Wang C L Charlie Chang K K Terry Yuen M F Matthew From laser scanned data to feature human model a system based on fuzzy logic concept Computer Aided Design 35 2003 241 253 Woodward CD Cro
69. constitute the selected scene Both sets are dynamics and give the designer the ability to redefine them at any time Furthermore the designer has the ability to check if his her modifications violate or not the rule set In cases where the designer desires to check the modifications against the rule set the system infers correctly if there is a violation or not In cases where the designer does not desire to check the modifications against the rule set the system ignores the rule set and updates the stratified representation as it should be The iterative design process of declarative modelling becomes supported by the machine with the contribution of the RS MultiCAD system The resultant declarative description is passed to the description phase of MultiCAD which in turn produces a set of alternative geometric solutions The MultiCAD solution generator operates on the discrete values of the variable ranges RS MultiCAD provides an automated and a manual way to Experimental Results 141 construct the resultant declarative scene description Both ways work properly on constructing the resultant declarative scene description In each iteration cycle the new declarative scene description reduces the initial solution space and produces more promising solutions Finally the RS MultiCAD system operates effectively provides a robust environment and supports properly all the goals for what has been designed The system user interface is user
70. corresponds to a DXF file format which is presented in Figure B 1 ren LWPOLYLINE 5 B 330 44 100 AcDbEntity 8 0 62 5 100 AcDbPolyline 39 5 90 4 70 1 43 0 38 0 10 0 410662348178138 20 0 774325506072875 10 8 63090526315789 20 0 774325506072875 10 8 63090526315787 20 6 75003400809717 10 0 410662348178117 20 6 75003400809717 1001 VDEXTRAPARAM 1071 1 1071 5 1071 5 1040 1 1000 Building 1 1040 0 1040 0 1071 1023410171 1071 1023410171 KE Figure B 1 The DXF file of a 3D box Appendix C The traditional geometric modeller The main task of RS MultiCAD project is to integrate the MultiCAD declarative modeller with a geometric modeller For this purpose the choice of the geometric modeller was based on the following requirements e An up to date commercial tool in order to support the present and any further extensions of the project e Portable in order to be transferred from one environment to another e Interactive in order to allow the designer to define and redefine the geometric requirements e Friendly in order the designer can easily produce a drawing e Accurate in order the geometric outputs to be sufficiently precise and satisfy their intended use e Integrative with other developing environment in order to be captured with the declarative modeller e Light in order to bind low capacity of memory storage VectorDra
71. ctiver olor oO 9 Active iode Vdr Modelicre le m s Active ayes 0 Eu ActeePer hie Verb e Tues y AcivePeriidh 0 DUX rc ActveTewteght 1 1 Acte ebay VAT mt alt r Achvel exte STANDARD n Ad ActiveTextVedustly VAT extVerBemem t3 Argae D E Argi COUNTER _CLOCKMISE r Ld T3 home DasePosnt Detsult neve FieProeme I Heverseon ioc Gres TANDARD 5 reina GigSnacOFF s HotchPettemns Deant leages Komm dm No Limits 10 0000 0 0000 1 2 00005 0000 m LineTypes ai ID UneType cale 1 Cy UrelecpiDopiy LWDION 2 wesS369gwTo9069 w9o5cs5i iu Height 12 Rotation angle 17 0780 0 9754 0 0000 CCS SNAP OFF DOF ORTHO OFF CSNAP OFF PAPER Ready Figure 4 31 An external geometric model 4 3 1 Scene modifications 4 3 1 1 Import geometric model RS MultiCAD Equal Height Longe Than Wider Than Equal Height Longer Than Wider Than Adjacent Noth Equal Height Longer Than Wider Than E qus Hei Longer Than Wider Than Adacent E oat Equal Height Longer Than Wider Than Adscent East Equal Height Longer Than Wider Than Adjacent Noth he Loegat Than High Wider Than High Longar Than Wide Relations ON GeoPropertios OFF Figure 4 32 Import of an external geometric model 124 Chapter 4 RS MultiCAD provides to the designer the ability to import a DXF file which has been created by another geometric modeler The decomposition tree is created based on the coordinates of the boxes
72. d Gin tion B Primitive 2 zu N ani 1 N N GEOMETRIC GEOMETRIC x PRIMITIVE PARAMETER TYPE OBJECT Zz l PROPERTY Relation w Cni TYPE id d TYPE Relation X Property N Formula Formula Ww RELATION m TYPE Knowledge DB FK 1 USES DECLARATIVE SCENE N NEL OBJECT OBJECT Co smit Y RELATION PROPERTY 1 SS 7 Parent w Related N N N Declarative pm Object_id N Value ii AN DECLARATIVE HAS OBJECT KS Scene DB Figure 3 8 The ER diagram of data and knowledge storage Thesis Proposal and Implementation 67 Every declarative description incorporates a set of objects Every object corresponds to an object type The declarative description also includes a set of object relations and a set of object properties The object relation corresponds to a relation type indicating the relation between two objects Every object property corresponds to a property type indicating the property which characterizes the object Thus the scene database contains the Declarative Scene Declarative Object Object Relation and Object Property table The scene database in connected with the multimedia database indicating which geometric solutions correspond to each declarative description Apart from that the scene database has
73. d clarative La convergence de l ensemble des mod les g om triques est r alis e par la mani re automatis e o le syst me RS MultiCAD fournit les propri t s g om triques appropri es la description d clarative de sc ne r sultante et manuellement o le concepteur ajoute d autres conditions la description d clarative r sultante de sc ne Pr cisons que la convergence de l ensemble des mod les g om triques de la mani re automatis e pr sente une pente raide la diff rence de la mani re manuelle o le concepteur peut d cider la pente peut tre plus douce Conclusions et Perspectives 149 Le syst me RS MultiCAD am liore la m thodologie de la mod lisation d clarative de sc ne par les points suivants Le syst me RS MultiCAD r duit le co t de mod lisation d clarative en permettant d abord de d finir une bauche de la sc ne par mod lisation d clarative et par la suite d affiner l bauche l aide d un modeleur g om trique int gr Le concepteur peut modifier une sc ne choisie et changer l ensemble de r gles en ajoutant des relations et ou des propri t s En outre le concepteur peut modifier l arbre de d composition de la description d clarative Par cons quent ces modifications m nent une description d clarative de sc ne r sultante qui correspondra un ensemble de solutions g om triques r pondant aux exigences du concepteur Le syst me RS MultiCAD fonctionne e
74. d all violated relations properties of the rule set and the control mechanism rolls the representation back to the previous state Thesis Proposal and Implementation 73 The modifications that can occur on the stratified model refer to abstract or leaf node and can be divided into two categories according to the geometric information that may be supplied by the designer In particular the declarative modifications are e Insert an abstract node by specifying its parent The insertion of an abstract node in the stratified model can be done by specifying firstly an already existing node of the model as its parent and secondly the nodes that become children of the new abstract node The result of such a change will affect the stratified representation since the object set changes e Delete a leaf abstract node The deletion of an abstract node will eliminate the sub tree where the abstract node is root The result of such a change will affect the object set and may affect the rule set as well The stratified representation must be updated in order to reflect the current state of the scene e Set unset relation property The designer changes the rule set by adding or deleting a relation or a property of a node Furthermore the geometric modifications are e Move an object The designer by providing the new position moves the object The stratified representation must be updated since the move may affect the objects of higher an
75. d or lower level of abstraction e Scale an object The designer specifies the scale factor of the object e Resize object The designer resizes the object by providing new values of the length width and or height of the object bounding box e Insert object The insertion of a leaf node is carried out by specifying the geometric characteristics of the object e Alter the extra geometric characteristics of an object In case where the shape of the object is complex the designer can alter the extra geometric characteristics that define the shape of the object 74 Chapter 3 3 4 4 The propagation policy The control module applies a specific propagation policy as soon as a modification occurs Golfinopoulos et al 06 The propagation policy is necessary in order RS MultiCAD system to recalculate and update the new position new dimensions of the objects that are related to the object under modification The main advantage of the propagation policy is the fact that the control module only updates the nodes that are related to the object under modification and leaves the rest nodes untouched The main criterion of the propagation policy is based on the position of the object under modification into the decomposition tree of the stratified representation An object under modification can correspond to a leaf node or an abstract node in the decomposition tree Whenever a modification occurs on a leaf node then the propagation starts from
76. d the data base of the prosthesis in which we can select a suitable kind of artificial knee joint model to customize for the patient It is only needed to change the local data of the corresponding CAD model to meet the different requirements of the patient In Stamati et al 05 is introduced the ByzantineCAD a geometric parametric CAD system for the design of pierced jewellery The ByzantineCAD is an automated parametric Related Research Areas 49 system where the design of a piece of jewellery is expressed by a collection of parameters and constraints and the user s participation in the design process is through the definition of the parameter values for reproducing traditional jewellery The design of the traditional pierced jewellery is based on the voxel oriented feature based Computer Aided Design paradigm where a large complex pierced design is created by appropriate placing elementary structural elements The final piece of jewellery is produced by applying a sequence of operations on a number of elementary solids An algorithm for scaling pierced patterns and designs has been introduced to enlarge pierced figures without altering the size of the structural elements used to construct them The reverse engineering process is focused on providing manually the elementary structural elements to the system instead of capturing these elements from existing artifacts and using them to reproduce the originals 2 4 3 Reverse engineering
77. dance et facilitent l applicabilit dans cette direction Ceci offre des produits meilleur march et de meilleure qualit car ils sont plus simples analyser et plus faciles changer que les pr c dents Le processus de conception est fr quemment consid r en termes de plusieurs phases s quentielles Pahl 96 conception conceptuelle conception pr liminaire ou d ensemble et conception d taill e Pendant la conception conceptuelle la fonctionnalit d sir e d un produit est d termin e les solutions de conception potentielles et leurs performances correspondantes sont d velopp es En outre les d penses pr vues sont estim es les restrictions aux solutions potentielles sont impos es et une sp cification g n rale du produit consistant en une description des concepts de conception avec des contraintes de fonction et de comportement est d finie Le fondement essentiel de la conception conceptuelle est de r aliser les objectifs la fonctionnalit et les propri t s satisfaisant les objectifs d un nouveau mod le Dans la conception d ensemble le foyer passe de la synth se du mod le conceptuel l exploration des solutions de conception potentielles Un ensemble de configurations r alisables du mod le est d fini suite l examen des diverses combinaisons des composants de mod les leurs contraintes et interactions ainsi que les ressources et les technologies disponibles pour garantir que tous les composants
78. deline which is defined in Miaoulis 02 A declarative description produces a set of alternative solutions that are stored in the multimedia database of MultiCAD Every geometric solution consists of a set of solution objects which in turn use geometric primitives which are expressed through geometric parameters Thus the multimedia database consists of a Geometric Solution table which is connected with the Solution Object and the Solution Geometric Value table The Solution Geometric Value table incorporates the values of the parameters of the geometric primitive that describes every solution object of every geometric solution Furthermore the multimedia database has a direct connection with the knowledge database of MultiCAD Additionally the knowledge database incorporates two tables the Geometric Primitive and the Geometric Parameter table The Geometric Primitive table contains all primitive shapes which are supported by the system The Geometric Parameter table includes all necessary parameters which characterize every primitive shape Figure 3 8 presents the entity relation diagram of data and knowledge storage 66 Chapter 3 GEOMETRIC SOLUTION ee Solution pup Object Multimedia DB A BN E t SOLUTION OBJECT id de P USES Min Val Max vale ue KNOWLEDGE DOMAIN LA Coma z Property Type_ i
79. dement Le syst me RS MultiCAD construit l arbre de d composition de la description d clarative de sc ne exploitant l information g om trique des solutions g om triques choisies Une autre mani re de construire l arbre de d composition est d exploiter la base de concept qui contient la repr sentation de concept et alors l arbre de d composition sera bas sur l organisation logique de la sc ne Bibliography Au et al 99 Autodesk 04 Bardis at al 05 Bardis et al 04 Benk et al 01 Benk et al 02 Bidarra 99 Bonnefoi 99 Bonnefoi et al 02 Au CK Yuen MMF Feature based reverse engineering of mannequin for garment design Computer Aided Design 1999 31 12 751 9 Autodesk DXF Reference 2005 February 2004 Bardis G Miaoulis G Plemenos D Intelligent solution evaluation based on alternative user profiles ICEIS 2005 Miami USA Bardis G Miaoulis G Plemenos D An intelligent user profile module for solution selection support in the context of the MultiCAD project 31A 2004 Limoges France Benk P Martin RR V rady T Algorithms for reverse engineering boundary representation models Computer Aided Design 2001 33 11 839 51 Benk P K s G V rady T Andor L Martin RR Constrained fitting in reverse engineering Computer Aided Geometric Design 2002 19 173 205 Bidarra A Validity maintenance in
80. designer should manage different solutions that appear similar Declarative modelling has preoccupied the scientific community during the last fifteen years Kochhar of MIT worked on declarative modelling in Kochhar 90 and Kochhar 94 26 Chapter 2 Kochhar accentuates the exploratory aspects of geometric modelling where the modelling is broken up into two sub tasks the design and the articulation The design comprises the creative aspects of modelling and the articulation comprises the specification of the geometry and the physical properties Kochhar introduces the Cooperative Computer Aided Design in Kochhar 90 and Kochhar 94 in order to facilitate the integration of generative and traditional modelling systems by allowing the designer to guide the generative system through successive rounds of automated geometric modelling The notion of generative modelling is very close to the notion of declarative modelling as in both cases imprecise descriptions can generate many solutions An experimental cooperative scene modeller was implemented for a generative system based on the formal language of schema grammars The Cooperative Computer Aided Design framework is based on the fact that a generative geometric modelling GGM system exists and generates a set of designs based on some designer defined constraints or properties the GGM system is supposed that does not produce perfect designs so it must guided to search for better design
81. droom and kitchen to change their position 3 4 5 The resultant declarative description As soon as the designer has completed all modifications on the scene RS MultiCAD results in a new declarative description which includes all modifications required by MultiCAD in order to generate in the next iteration more promising solutions by reducing the initial solution space The question that arises is which relations and properties must be included in the new declarative description RS MultiCAD replies to that question by providing two optional ways manual and automated Golfinopoulos et al 06 In particular RS MultiCAD in the manual way results in a new rule set that is based on the initial rule set along with the new relations and properties that have been changed by the designer In this way RS MultiCAD offers the designer the possibility to drive the system to generate a solution space that is closer to his requirements Figure 3 12 The generalization factor 76 Chapter 3 Furthermore the automated way is based on the generalization factor GF Every hierarchical decomposed tree is divided in distinct levels of detail The generalization factor is related to levels of detail and its values vary from 1 to maximum tree depth The rule set that accrues from the automated way is based on the initial rule set along with all designer modifications and also all pure geometric properties that are implied from the gen
82. ducts These parts define in turn assemblies which they define feature models Typical examples of features are holes slots pockets protrusions et cetera for general mechanical components There are many types of features and can be categorized according their function complexity and level of detail of the geometric description According to their function features are categorized into form features material features and pattern features Besides features are distinguish by their degree of complexity into elementary features which are basic simple and cannot be decomposed into more simple features and compound features Bronsvoort 93 which are composed of several other features Furthermore there are features which are described by parameters they are not evaluated into a precise geometric description their exact shape is not represented and it is merely implied Explicit features have their shape explicitly described by a geometric model while their resulting geometry is evaluated Bronsvoort 93 Features use properties for their definition Intrinsic properties refer to the fact that they affect only the feature itself Extrinsic properties affect and depend on the properties of other features Other characteristic properties of the features are derived and non derived properties Derived properties are such their values do not determined by the user but derived from other features It has been often remarked that fea
83. e 4 25 Save the geometric solution 4 2 3 Reduction of the solution space RS MultiCAD provides two main ways for MultiCAD iteration the automated and the manual way Figure 4 26 illustrates the two alternative ways for reducing the solution space 118 Chapter 4 RS MultiCAD egi edo oa alaa pleine Specty the desiable reduction ol the solution space CLG automaed mo pec the genes aksahon actor a M Hemm Color 2955 255 255 D a 15 9694 8 5958 0 0000 Figure 4 26 Reduce the solution space 4 2 3 1 Automated way In each MultiCAD iteration the RS MultiCAD system adds pure geometric properties to the declarative description that depends on the generalization factor The designer specifies the generalization factor and then RS MultiCAD produces the respective declarative description The first iteration of MultiCAD produces a set of alternative geometric solutions by supplying only the pure geometric properties of the object site and the rule set In the second iteration the declarative description is additionally provided with the pure geometric properties of the next level of detail In other words the pure geometric properties of the objects aux_building long building and high building are provided by RS MultiCAD to the declarative description In the third iteration the resultant declarative description is supplied furthermore with the pure geometric proper
84. e 4 43 Resize kitchen to a new width In case the designer resizes the object vcorridor to a new width equals to 4 5 the modification is canceled since the position is not available Higher Than Long Wider Than High Wider Than Long Relations ON GeoProperies OFF Figure 4 44 Position not available Experimental Results 133 Changing the width of the object vcorridor the position of the object dining room alters in order to be adjacent south to object bedroom RS MultiCAD alters the position of the object kitchen in order to be adjacent south to object dining room The new position of the object kitchen is occupied partially by the object vcorridor and this is the reason why the modification is canceled The result is illustrated in Figure 4 44 In case the designer resizes the object vcorridor to a new length equals to 1 5 the modification is applied The modification is propagating in a circular way affecting all brothers According to the rule set the new length dimension of the object vcorridor affects the position of the object living room which in turn affects the position of the objects bedroom and office The object office in turn affects the position of the object bathroom which in turn affects the positions the objects hcorridor and kitchen The ancestors of the object kitchen are updated accordingly The result in top view i
85. e by the modeller The solution adopted at the end of the process will thus check the whole of the criteria of description A declarative modeller can also handle other information than purely geometric The designer can describe a desirable scene on high level of abstraction For example the weight of an object design can be a criterion taken into account for a relation between several objects in the design process Declarative modelling is adapted to the integral management of the design process The same object can be perceived differently according to the domain which means that the same object looks like differently and its usefulness varies in several domains Besides another designer could describe in another way the same object by using different properties Declarative modelling can deal with the whole of the process of design since various properties are checked on the design process On the other hand the interpretation of description is a significant problem of the declarative modelling since the handling of high level concepts often leads to various interpretations The majority of declarative modellers use the exploration of a universe to seek the scenes that meet the properties of description This search can lead the designer to solutions which he did not consider However the presentation of all the possible solutions can be a deliberated choice of certain modellers regardless the number of the solutions Thus the
86. e description The principle source of non geometric information is Related Research Areas 53 the sub scene names in the declarative description These manes typically contain an explicit high level description of the meaning of the sub scene and are maintained by the labelling system as a set of properties called labels After a geometric representation has been created a special process is used to traverse the hierarchical description of the scene and to match decomposed sub scene names to labels This process requires the cooperation of the user since the label list must be adapted to the set of sub scene names The geometric to declarative representation conversion process converts a geometric instance to declarative description by identifying all objects without parent determining if the bounding boxes overlap and if so decompose the hierarchical objects generating a scene hierarchy using a binary sub scene agglomeration and describing each sub scene and their relationships The scene inclusion process provides a means for the inclusion of previously generated scenes in a declarative description The designer can associate a sub scene in the declarative description with an existence scene or a list of existing scenes Sellinger connects successfully a traditional geometric with a declarative modeller gives special emphasis on retrieving the appropriate knowledge from the designer and gives special attention on man machine interaction
87. e la possibilit d importer un mod le g om trique qui arrive d un autre modeleur g om trique classique et d exporter le mod le g om trique dans un format appropri de dossier voir Appendix B afin que le concepteur le manipule l aide d un autre modeleur g om trique classique Le module d extraction emploie la connaissance sp cialis e dans le domaine qui arrive de la base de connaissance de MultiCAD voir Appendix A afin d extraire toutes les relations valides et les propri t s des objets partir de la sc ne choisie Le module de contr le est responsable pour la construction la manipulation et la mise a jour de la repr sentation stratifi e La construction de la repr sentation stratifi e est accomplie par une approche de descendante de haut en bas et est bas e sur l information g om trique des objets qui constituent la sc ne choisie Quand le concepteur effectue des modifications sur la sc ne choisie le module de contr le manipulation et met jour la repr sentation stratifi e afin de refl ter le statut r el de la sc ne choisie La manipulation et la mise Jour de la repr sentation stratifi e sont bas es sur une politique de propagation o les anc tres et les descendants de l objet susceptible de modification doivent tre contr l s et mis jour Le concepteur a la capacit d effectuer des modifications d claratives qui affectent premi rement la couche d clarative de la repr sentation s
88. e object i Object A Position X Is X4 Object A Position Y Is YA Object A Position Z Is 2 Z4 X Object A Length Is X X Object A Width Is Y2 Y Object A Height Is Z Z Appendix B DXF format The DXF format is a tagged data representation of all the information contained in a CAD drawing file Tagged data means that each data element in the file is preceded by an integer number that is called a group code A group code s value indicates what type of data element follows This value also indicates the meaning of a data element for a given object or record type Virtually all user specified information in a drawing file can be represented in DXF format A DXF file is divided in five major sections The header section witch contains the settings of variables associated with the drawing Each variable is specified by a 9 group code giving the variable s name followed by groups that supply the variable s value The Classes section which holds the information for application defined classes whose instances appear in the BLOCKS and ENTITIES sections of the database The Tables section contains several tables each of which can contain a variable number of entries The Block section contains an entry for each block reference in the Drawing The Entities Section witch describes all the drawing entities Some group codes that define an entity always appear others are optional and appear only if their values d
89. e performed with or without taking into consideration the rule set which consists of predefined relations Thesis Proposal and Implementation 87 and properties of the objects The main idea that underlies the handling of the move operation is based on the calculation of a general bounding box that embodies all related objects Algorithm 3 4 presents the move operation MOVE object B Begin If respect rule set Then find all related objects End If calculate bounding_box with all related objects calculate bounding_box with new positions of all related objects If bounding box in site Then If space available Then update all related objects with new positions update all descendants of all related objects with new positions update all ancestors of all related objects with new positions dimensions If respect rule set Then check rule set for all related objects check rule set for all descendants of all related objects check rule set for all ancestors of all related objects If OK Then MoveCode success Return Else backtrack all ancestors to old positions dimensions backtrack all descendants to old positions backtrack all related objects to old positions call explanation module MoveCode rule set violation Return End If Else MoveCode success End If Else MoveCode position not available Return End If Else MoveCode out of site Return End If End ax Algorithm 3 4 Move operation 8
90. e possibility of scene description using properties which can be either precise or imprecise Plemenos 91 Plemenos 95 Lucas et al 90 and differentiates from traditional geometric modelling since does not require precision modelling tools Declarative modelling is a total approach of the designing process Plemenos et al 02 Declarative modelling permits the designer to describe a desirable scene by only giving some expected properties of the scene and letting the declarative modeller find alternative solutions if any verifying these properties The designer can describe a scene intuitively in declarative modelling An abstract description and a vague description of the properties of the desired scene are acceptable by the declarative modelling When the designer describes a scene intuitively in terms of common expressions Related Research Areas 25 the described properties are in many cases imprecise The imprecision of a described property is presented when many values can satisfy that property on one hand while on the other hand is presented due to the fuzziness of a property Plemenos et al 02 Both cases lead declarative modelling to be characterised as a time consuming modelling approach The designer has to supply a description of the desired scene from the designer along with the relations of the different parts of the scene The designer does not concern about checking the properties of the desired scene this is don
91. e rule set The additional spatial 114 Chapter 4 reflective relations and properties are presented below The tables 4 4 4 5 4 6 present the additional relations and properties and are illustrated in Figure 4 23 Object Relation aux_building wider than long high_building higher than long Table 4 4 Additional Reflective Relations Object1 Relation Object2 aux_buildng lower than wider than high_building aux_building wider than shorter than long_building long_building longer than lower than high_building living room 5 equal length equal width equal height play room 6 living room 5 equal length equal width roof 13 play room 6 equal length equal width roof 14 flat 7 equal length equal width roof 15 kitchen 8 equal width equal height bathroom 10 kitchen 8 equal width equal height bedroom 10 garage ll equal length equal width equal height storage 12 storage 12 equal length equal width roof 16 Table 4 5 Additional Spatial Relations Experimental Results 115 Object1 Property Value aux_building is long low is tall high high_building is long is wide low long_building is wide low living room 5 is tall is long is wide low play room 6 is wide low roof 13 is tall no roof 14 is tall no flat 7 is tall low kitchen 8 is tall is long is wide low garage ll is long is wide low roof 16 is tall no roof 1
92. e toolbar provides many options to the designer to set the view point to top bottom left right front back southwest southeast northeast and northwest Besides the designer can start a continuous motion with the button by rotating the coordinate system around X and or Y Axis Furthermore the designer can shade the objects between polygon faces and colouring the object with its colour by using the Wf button or display the objects using lines and curves to represent the boundaries by using the button The amp l button combines the shade with the wire button Additionally the designer can zoom in out the display and move the objects in the same direction by using the V7 button The button is used for perspective view On the File menu the designer can select menu commands for opening an existing database in order to load a geometric solution saving a geometric solution and a declarative Experimental Results 97 description in a database and also opening and saving files with DXF file format see Appendix B On the Scene menu the designer can set the view point of the scene through menu commands to top bottom left right front back southwest southeast northeast and northwest and also activate and deactivate the toolbar The Change menu consists of menu commands for moving an object of a selected geometric solution scaling resizing an object inserting a new object and deleting an e
93. ecting the garage_6 and the roof_8 object then the object site is selected 4 2 Case I Internal MultiCAD geometric model An initial declarative description produces a set of alternative geometric solutions The Tables 4 1 4 2 and 4 3 illustrate the spatial reflective relations and properties respectively which the designer has declared during the declarative description phase and consist the rule set A random solution is selected which is illustrated in Figure 4 1 and is considered as the initial state for the below scene modifications The stratified representation is presented in Figure 4 2 Object1 Relation Object2 living room 5 adjacent under roof 13 play room 6 adjacent under roof 14 roof 15 adjacent over flat 7 storage 12 adjacent under roof 16 storage 12 adjacent over garage ll bathroom 9 adjacent east kitchen 8 bathroom 9 adjacent west bedroom 10 Table 4 1 Spatial Relations Experimental Results 99 Object Relation building 3 longer than wide Table 4 2 Reflective Relations Object Property Value building 3 is tall medium Table 4 3 Properties Geometric Layer geometric properties geometric properties geometric properties geometric properties geometric properties has geometry geometric properties geometric properties geometric properties geometric properties has ge geometric properties geometric prop
94. ed through dialog boxes The use description is translated into an internal model which is expressed in terms of rules and facts PolyFormes in order to generate solutions uses an inference engine which applies rules to the facts and creates new facts and explores the solution space Figure 2 1 presents an example of polyhedron generated by PolyFormes Figure 2 1 Example of polyhedron generated by PolyFormes e PastoFormes In Colin 88 Colin 90 PastoFormes is a declarative modeller based on elementary polyhedrons Objects are modelled by joining elementary polyhedrons e UrbaFormes In Le Goff 90 is presented a declarative modeller for urban morphology This modeller proposes to establish in a declaratory way a route and allows discovering urban aspects of a given city e MultiFormes In Plemenos 91 is presented a declarative modeller based on hierarchical decomposition further details in 2 2 5 e SpatioFormes In Poulet 94 a declarative modeller is presented which allows the description and the generation of three dimensional scenes constructed by matrices of voxels 28 Chapter 2 FiloFormes In Pajot Duval 94 is presented a declarative modeller which receives a user description and produces all possible configurations of segments VoluFormes In Chauvat 94 Chauvat 95 is presented a declarative modeller for spatial control The user defines boxes in the space whose purpose is to check the growth of f
95. eling Constraint evaluation for the hierarchical decomposition approach International Conference WSCG 97 Plzen Czech Republic Poulet F Mod lisation d clarative de sc nes tridimensionnelles par num ration spatial Le projet SpatioFormes Th se de doctorat Rennes Juin 94 Poulet F Lucas M Modelling Megalithic Sites Proceedings of Eurographics 96 Poitiers France 1996 pages 279 288 Prabhakar S Henderson MR Automatic form feature recognition using neural network based techniques on boundary representations of solid model Computer Aided Design 1992 24 7 381 93 Ravani I Makris D Miaoulis G Plemenos D Concept Based declarative description subsystem for CADD 3IA 2004 Conference Limoges France 2004 Ravani I Makris D Miaoulis G Constantinides P Petridis A Plemenos D Implementation of architecture oriented knowledge framework in MultiCAD declarative scene modeling system Ist Balcan Conference in Informatics Thessaloniki Greece 2003 Requicha X Representations for rigid solids theory methods Bibliography 159 Ruchaud 01 Sagerer et al 97 Sanchez et al 03 Schumaker 93 Sellinger 95 Sellinger 97 Sellinger 98 Simon 96 Siret 97 and systems Computing Surveys 1980 12 437 464 Ruchaud W Etude et r alisation d un moteur de r solution de contraintes g om triques pour la mod lisation
96. en generated by MultiCAD into a declarative model In the next sub section the architecture of the proposed RS MultiCAD system is presented First of all this sub section starts with the presentation of the data and knowledge storage and indicates the interrelations between the databases A special attention is given on describing the dynamic stratified representation The stratified representation overcomes the problems of capturing geometric and declarative information by incorporating a declarative and a geometric layer RS MultiCAD system semantically understands a selected scene by exploiting the knowledge base of MultiCAD and permits a series of scene modifications to designer in order to alter the selected scene The stratified representation absorbs the designer modifications by activating a propagation policy which correctly determines the transition of a selected scene from one state to another Besides RS MultiCAD system provides the possibility to the designer to determine how the resultant declarative description is constructed which will be passed to the declarative description phase in the next iteration of MultiCAD The last sub section is dedicated to the implementation of RS MultiCAD It presents the geometric representation the main algorithms that RS MultiCAD prototype incorporates such as the knowledge extraction and the construction of the stratified representation Finally this sub section presents the algorithm for the
97. ene the designer specifies the properties and relations that are necessary from his point of view A property to a node operates as a constraint and obliges the object to respect that specific property since it will participate to the generation phase Figure 2 8 illustrates a typical decomposition tree along with the relations and the properties The example is adopted from Plemenos 95 36 Chapter 2 Residence House is on the left of Garage Garage is 70 top rounded House is higher than large House is higher than wide a Roof is on the top of Walls Walls Roof Roof is 70 top rounded House Garage Figure 2 8 A typical example of a decomposition tree The generation phase of MultiFormes produces objects which are described by their bounding boxes Each of these bounding boxes is described by a starting position in terms of X Y and Z coordinates and a displacement vector defining the width the height and the depth of the associated bounding box Each bounding box is described by at least six numeric variables Besides some other relevant information is associated like the colour or the texture of the object MultiFormes associates the properties with the starting position and the size of the bounding box of the object A workspace is defined and all bounding boxes of objects take place in this workspace MultiFormes uses a numeric constraint solver and several
98. engineering is used in order to construct a 3D model from a physical model Even if it is out of scope of this thesis a brief presentation is given Furthermore the reverse engineering in feature based modelling is sketched in order to highlight the field of feature recognition Finally in the declarative modelling approach reverse engineering is used to transform geometric model which corresponds to a geometric solution into a more abstract model the declarative model 2 1 Geometric modelling Geometric modellers are powerful design tools with which complex shapes can be modelled edited manipulated and graphically verified There are three types of geometric representations 1 e wire frame surface and solid models Mortenson 85 Wire frame models only contain vertex and edge information about objects and are therefore unsuited to 27 Chapter 2 reasoning about the transformation of solid objects However lack of explicit surface information can lead to models which are ambiguous incomplete or even impossible to manufacture as they can correspond to no physical 3D object Goldman 87 These drawbacks led to the search of more sophisticated schemes and gave way to surface and solid modellers Similarly surface models suffer from only containing face information while solid models are capable of a complete and unambiguous geometric description of objects Surfaces are used explicitly to describe an object in surface modellers Mo
99. er 4 The system recalculates the relations of the object kitchen_8 that are valid The object bathroom_9 is adjacent west to the object kitchen_8 which belongs to the rule set but the relation is not valid any more and disappears from the declarative panel The result is illustrated in Figure 4 7 In case the designer moves the object kitchen_8 to a new position that is occupied by another object the move operation is canceled Every time the designer wants to move an object two main checks take place The new position must be available which means that none of the rest objects occupies the specific position Besides the new position must be included in the object site which is the root of the scene In the current example as the move of the object kitchen_8 is propagated to its brothers the new position of the object bedroom_10 is occupied by the object garage_11 and the modification is canceled The result is illustrated in Figure 4 8 RS MultiCAD eei eic el 9 vw S oleo mx burn nek NN Wing oom 5 GeoPropety Vae play eom E Poston Xis 7 tool 13 Postion Y Is 4 icol 14 Posten 2 ls 0 erg buking I 1 thet Weds 2 kachen 0 Hogi z buhroom 9 becom n tool 15 a tabs Coar 0772557 255 guage 11 iz storage Type kitchen too 16 Relation jOtet hotet Than bedroom 10 AR D L 9 4095 0 0000 Relations ON
100. eralization factor The nodes that provide their pure geometric properties to the rule set are the nodes that belong to the same and higher level of detail if and only if these nodes have descendants If the designer set the generalization factor to the maximum tree depth all nodes of the decomposition tree provide their pure geometric characteristics to the resultant rule set Figure 3 12 schematically shows which pure geometric properties are included in the rule set according to generalization factor If the generalization factor equals to 1 the pure geometric properties of the root node are included in the rule set If the generalization factor equals to 3 the nodes that provide their pure geometric properties to the rule set are the nodes that belong to the first second and third level of detail except the nodes which have none child As it is obvious if the generalization factor equals to 4 the rule set is enriched with pure geometric properties of all nodes which it will lead to only one geometric solution in the next iteration of MultiCAD 3 5 RS MultiCAD prototype RS MultiCAD has been implemented on the Microsoft Visual Studio NET platform by using the C programming language and embodies the VectorDraw Viewer component see Appendix C 3 5 1 Geometric representation RS MultiCAD receives a geometric model which contains the pure geometric properties of the objects that constitute the scene along with any extra geometric ch
101. erche Septembre 1995 Farin G A construction for visual C1 continuity of polynomial surface patches Computer Graphics and Image Processing 1982 20 272 282 Fisher B Robert Applying knowledge to reverse engineering problems Computer Aided Design 36 2004 501 510 Foley van Dam Feiner Hughes Computer Graphics Addison Wesley Publishing Company 1999 Goldman X The role of surfaces in solid modeling Farin G editor Geometric modelling Philadelphia SIAM Press 1987 154 Bibliography Golfinopoulos et al 04 Golfinopoulos et al 05 Golfinopoulos et al 06 Gordon 69 Gregory 89 Han et al 98 Henderson 84 Kim 92 Kochhar 90 Kochhar 94 Golfinopoulos V Dragonas J Miaoulis G Plemenos D 2004 Declarative design in collaborative environment 31A 2004 Limoges France Golfinopoulos V Miaoulis G Plemenos D 2005 A semantic approach for understanding and manipulating scenes 3IA 2005 Limoges France Golfinopoulos V Stathopoulos V Miaoulis G Plemenos D A knowledge based reverse design system for declarative scene modeling ICEIS 2006 Paphos Cyprus Gordon WJ Spline blended surface interpolation through curve networks J Math Mech 1969 18 931 952 Gregory JA A C2 polygonal surface patch Computer Aided Geometric Design 1989 6 69 75 Han J Regli WC Brooks S Hint based rea
102. erse engineering Comput Integrated Manufact Syst 1995 8 3 193 204 Colin C Towards a system for exploring the universe of polyhedral shapes Eurographics 88 Nice France pp 209 220 Colin C Mod lisation d clarative de sc nes a base de poly dres l mentaires Le projet PastoFormes Th se de doctorat Universit de Rennes I IFSIC D cembre 1990 Colin C Desmontils E Martin J Y Mounier J P Mod le Bibliography 153 Colin et al 98 De Rose 90 de St Germain et al 97 Degen 90 Desmontils 95 Farin 82 Fisher 04 Foley et al 99 Goldman 87 utilisateur d une modeleur d claratif Journ es Modeleurs G om triques Grenoble 17 19 Septembre 1997 Colin C Desmontils E Martin J Y Mounier J P Working modes with a declarative modeler Computer Networks ans ISDN Systems 30 1998 1875 1886 De Rose TD Necessary and sufficient conditions for tangent plane continuity of B zier surfaces Computer Aided Geometric Design 1990 7 165 179 de St Germain HJ Stark SR Thompson WB Henderson TC Constraint optimization and feature based model construction for reverse engineering Proc ARPA Image Understand Workshop 1997 Degen WLF Explicit continuity conditions for adjacent B zier surface patches Computer Aided Geometric Design 1990 7 181 189 Desmontils E Les modeleurs d claratifs rapport de rech
103. erties geometric properties geometric properties geometric properties has geometry has geometry ometry geometric properties bmetry has geometry has gebmetry has gepmetry Rabat geometric properties EE S D Declarative Layer has geometry has geometry has gepmetry site o children parent parent parent aux long high building 79 building ne pbuilding a gt o a sr n Av previous children S children parentparent parent parent parent parent parent nn children parent previous parent living rooms K previous storage 12 play room6 Le previous garage roof13 11 K previous AC roof14 b flat7 RR children parat parent parent roof15 roof16 nex nex nex next next 7d K previous x previous bedroom 10 bathroo kitchen8 iid L4 previous next nex K previous Figure 4 2 The stratified representation of Case I 100 Chapter 4 4 2 1 Scene modifications 4 2 1 1 Object rename The name of the object can be renamed by clicking on the object name and typing the new name that the designer prefers The objec
104. es r sultats exp rimentaux qui sortent de la fonctionnalit soulign e du syst me propos La premi re sous section pr sente un bref mode d emploi de l environnement de travail propos et dans la deuxi me et la troisi me sous section illustrent des cas diff rents Enfin le chapitre 5 pr sente les remarques de conclusion et les nouvelles directions pour la future recherche Chapter 2 Related Research Areas The objective of this chapter is to illustrate the main research areas of this thesis Declarative modelling transforms an abstract model into a set of geometric representations so a brief overview of the basic geometric representations is presented along with the advantages and the disadvantages of geometric modelling Besides the state of the art of declarative modelling is presented describing the general and dedicated declarative modellers the declarative conception cycle and the iterative design process of declarative modelling Afterwards the levels of abstraction and the levels of detail of declarative modelling are discussed A special attention is given on the MultiFormes system and a detail presentation of the MultiCAD system is illustrated since it will be the system framework under which the proposed system of this thesis will develop Finally the reverse engineering paradigm is presented which permits the transformation of one model into another one In the framework of geometric modelling reverse
105. esentation The need of representing geometric and declarative information leads to an approach of using the stratified representation Sagerer 97 The stratified representation is an intermediate level model necessary for connecting the declarative with the geometric model and embodies the two distinct interconnected layers of representation the declarative layer which represents the scene description with the hierarchical decomposition and the geometric layer which encapsulates the geometric aspects of the objects Golfinopoulos et al 06 The geometric layer of the stratified representation is based on the bounding box position and dimensions of each object which are expressed through the object pure geometric properties along with any extra geometric information that can determine the shape of the object RS MultiCAD inputs a geometric model which has been produced by the solution generator That geometric model apart from the geometric information of all objects that constitute the scene provides their object type as well The stratified representation is a dynamic semantic net with nodes and directed arrows The node encapsulates declarative information of the object and the directed arrow reflects either the relation of the object with other objects or the object property or the level of detail Every node is connected with a geometric node which includes all relevant geometric aspects of the object of the geometric layer Figure
106. euvent tre pr cises ou impr cises et ce sans indiquer la fa on d obtenir une sc ne avec ces propri t s La mod lisation d clarative lib re le concepteur de l obligation de d finir les propri t s g om triques des entit s et facilite la description de sc ne en requ rant uniquement quelques propri t s d j connues La mod lisation d clarative traite de la description vague des objets et offre au concepteur un environnement pratique pour l expression pr cise de l id e de conception congue Plemenos et al 02 Une approche sp ciale de la mod lisation d clarative est la mod lisation d clarative par d composition hi rarchique Plemenos 91 Plemenos 95 Cette approche fournit au concepteur la capacit de d crire la sc ne d sir e en d composant la sc ne de mani re descendante de haut en bas des niveaux de d tails diff rents et facilite la description de sc nes complexes Au contraire les syst mes de conception conventionnels assist s par ordinateur encouragent le concepteur employer une approche de conception ascendante de bas en haut La mod lisation d clarative de sc nes est bas e sur le cycle de conception d claratif qui consiste en trois phases s quentielles La premi re est la description de sc ne d clarative o le concepteur d crit comment elle il per oit la sc ne d sir e en d finissant des propri t s de la sc ne ou sans les d finir La seconde est la phase de g n ration o
107. fi e est constitu de la couche d clarative et la couche g om trique La couche d clarative incarne la description de sc ne d clarative avec la d composition hi rarchique La couche g om trique englobe la repr sentation g om trique des objets qui constituent la sc ne choisie La couche d clarative de la repr sentation stratifi e est un filet s mantique dynamique avec des n uds qui correspond aux objets de la sc ne choisie et aux fl ches orient es qui marquent les relations et les propri t s des objets La couche g om trique de la repr sentation stratifi e pr sente la repr sentation g om trique des objets qui est exprim e par la position et les dimensions de la boite englobante des objets et de toutes les autres caract ristiques g om triques suppl mentaires qui d finissent la g om trie des objets complexes Conclusions et Perspectives 145 Le syst me RS MultiCAD est un syst me bas sur la connaissance qui utilise la connaissance essentiellement sp cialis e en architecture pour la conception de b timents La structure du syst me RS MultiCAD est modulaire et se compose de cinq modules principaux Le module d import export est responsable de la communication avec le syst me de gestion de base de donn es Toutefois il supporte l entr e et le stockage de la solution g om trique avec le stockage de la description d clarative de sc ne qui en d coule De plus le module d import export traite d
108. fy the desirable scene in several levels of detail allowing thus a top down design Thus the structure of a scene can easily be represented by a hierarchical decomposition tree Apart from the description of the scene the decomposition tree is used in the generation phase as well Declarative modelling by hierarchical decomposition is an approach that allows the designer to describe even more complex scenes Plemenos 91 Plemenos 93 Plemenos et al 97 Bonnefoi et al 02 The major advantages of the declarative modelling by hierarchical decomposition are the following e The designer can describe the desirable scene in a progressive manner at various levels of detail in logical and spatial way The level of detail of a sub part of the desired scene can differentiate from the level of detail of another sub part enforcing the locality and allowing the designer to specify the levels of detail as he she deems Related Research Areas 35 e The hierarchical decomposition authorises the factorisation of properties and specially the placement properties e The designer can describe locally the properties without worrying about the rest of the scene Thus the hierarchical decomposition permits the independence between nodes of the decomposition tree with the same ancestor e The designer can control the generation process since it can be made in various levels of detail Thus the designer can stop the generation process at a gi
109. g to the rule set is violated 106 Chapter 4 M RS MultiCAD 9 wi3 eee 130 120 200 le bathaoom Shoser Than bedroom 10 ex Se E 4 6762 4 3327 0 0000 Relations ON GecPropestes OFF Figure 4 10 Resize bathroom 9 The descendants of the object flat 7 resize their lengths accordingly The lengths of the object kitchen 8 bathroom 9 and bedroom 10 becomes 1 4 1 4 and 42 respectively It must be pointed out that the lengths rate of the descendants remains the same as before the modification The result is illustrated in Figure 4 11 f RS MultiCAD z fi f Figure 4 11 Resize flat 7 to a new length Experimental Results 107 TE RS MuttiCAD CIE Figure 4 12 Violation of resize flat 7 In case the designer resizes the object flat 7 to a new length and width equal to 5 the reflective relation longer than wide of the object long building is violated and the modification is canceled The result is illustrated in Figure 4 12 M RS MultiCAI 110 5898 14 2633 0 0000 Figure 4 13 Resize storage 12 to a new height 108 Chapter 4 In case the designer resizes the object storage 12 to a new height equals to 3 the modification is applied The object storage_12 is adjacent under to the object roof_16 and adjacent over to the object garage_11 according to the rule set The new position of the object s
110. he different types of knowledge and information application and interaction control e The process layer comprises functions such as generation or understanding between the different levels of models converting the different types of the same level s models e The information and knowledge management layer is used for structuring management searching and exploitation of the different databases MultiCAD follows the declarative conception cycle where in the description phase the designer describes the desired scene by defining the scene s decomposing objects their properties and relations in many ways Related Research Areas 39 e Tree formed representation This form explicitly represents the hierarchical decomposition of the scene Figure 2 10 presents the working space of MultiCAD e Text formed representation It is expressed in a formal Prolog like language Plemenos 95 representing the internal declarative representation of the scene e Representation in an object relational database Miaoulis 02 The scene s description is stored as an assembly of objects having properties and being related to each other through relations MultiCAD Scenes Solvers Visualization eae Object Name Type doro ham bathroom site 1 building 3 flat 7 Save Add Object Delete Objec kitchen_8 bathroom S Properties Relations Graph View pedoom 1D Becr Relion 7 bet2 roof 15 3
111. he solution space Case I Table 4 8 Manual reduction of the solution space Case I Table 4 9 Properties Case II Table 4 10 Automated reduction of the solution space Case II Table 4 11 Manual reduction of the solution space Case II Table B 1 Group code value types Table B 2 Group codes 67 68 69 69 98 99 100 114 114 115 119 121 127 136 138 172 172 List of Algorithms Algorithm 3 1 Convert a linked list into a decomposition tree Algorithm 3 2 Extract relations and properties Algorithm 3 3 Compute the spatial relations Algorithm 3 4 Move operation Algorithm 3 5 Scale and resize operation Algorithm 3 6 Insert operation Algorithm 3 7 Set the generalization factor 82 83 84 87 89 90 92 Chapitre 1 Introduction Lors des derni res d cennies la mod lisation g om trique est devenue un outil pr cieux pour diverses applications dans de nombreux domaines tels que la conception industrielle et architecturale la fabrication ainsi que l ing nierie lectrique et m canique La conception et la fabrication d objets aussi diverses que des b timents des voitures des bateaux etc exploitent les avantages de la technologie naissante En cons quence les objets physiques ont t largement remplac s par des mod les g om triques puisque les syst mes assist s par ordinateurs imposent cette ten
112. hen_8 248 bathroom 9 249 bedroom 10 250 garage 11 251 storage 12 252 roof 16 ELTTTTTTTITITTITITTTITITTTTTTTTT BREBRBIBSASISSHRHRIR IRA RR oS Figure 4 24 Save the declarative description Experimental Results 117 4 2 2 2 Save the geometric solution Apart from saving the declarative description the designer can store the geometric solution as well at any time A geometric solution can be stored in the Multimedia Database of MultiCAD but can be stored in DXF format as well The geometric solution uses three interconnected tables in order to be stored The solution table relates every geometric solution with the respective declarative description The solution object table contains information such as the shape of the objects of the geometric solution The solution geo value contains the dimensions of the bounding box of each object along with any extra geometric characteristics that may have the object Figure 4 25 shows a typical example of a stored geometric solution LE B Table descnp scene auth 1 a house of santorini dimitris makris 10 vassilist vassilis 11 vassilis2_dm vassilis 12 vassilis3 vassilis 13 vassilisd vassilis 15 vassilisS vassilis 17 BogTest BavihZ 24 LOGTestScene Baz 25 MultsCAD Editor Sce MuliCAD Edo news REO OT v 5 solution Table RSS RE N S 1800 24 Receed 1 4 F r 9 EPI Ibe of 215 7 9 9 9 3 3 55 CRIER jHEBEBZZSSsasstshu Figur
113. historical evolution of the entities in the evaluated boundary model The current feature based modelling approach has the following drawbacks Bronsvoort 01 e The meaning or semantics of features is poorly defined limiting the capability of capturing design intent in the model Moreover semantics are often not adequately maintained during modelling An answer to this drawback is given by Bidarra 99 where the definition of the semantic feature modelling is taken place In semantic feature modelling the feature specification is done in feature classes which are structured descriptions of all properties of a given feature type A semantic feature model is developed to represent a product and consists of a feature dependency graph which is a set of interrelated features and constraints and the geometric representation The validity maintenance monitors each modelling operation in order to assess the conformity of all features in the semantic feature model Related Research Areas 43 e The product development phases lack product models with multiple feature views In general current only form feature views are supported by multiple view feature modelling systems e The feature modelling systems does not support yet a collaboration environment of several users in product development On one hand there are similarities between feature based and declarative modelling The main similarity is based on the fact that both modelling a
114. iffer from the defaults The end of an entity is indicated by the next 0 group which begins the next entity or indicates the end of the section Group codes also define the type of the associated value as an integer a floating point number or a string the following table B 1 of group code ranges shows some of the basic types and their corresponding group code Autodesk 04 172 Appendix B Group Code Value Types 10 39 Double precision 3D point value 40 59 Double precision floating point value 90 99 32 bit integer value 100 String 255 character maximum less for Unicode strings 290 299 Boolean flag value 320 329 String representing hex handle value Table B 1 The following table B 2 shows some of the most commonly used group codes Autodesk 04 Group Code 0 Text string indicating the entity type 1 Primary text value for an entity 2 Name attribute tag block name andsoon i istsi lt is sSSSCS 5 Entity handle text string of up to 16 hexadecimal digits 6 Linetypename 0000000000000 8 Layername 0 0000 10 Primary point this is the start point of a line or text entity center of a circle and so on DXF X value of the primary point followed by Y and Z value codes 20 and 30 11 18 Otherpoints 0 000000000000 DXF X value of other points followed by Y value codes 21 28 and Z value codes 31 38 39 Entity s thickness if nonzero Table B 2 DXF Format 173 A typical three dimensional box
115. ions and properties of the rest existing objects 3 5 5 5 Extra geometric characteristics operation Apart from the topological modifications that can be applied the designer can affect the geometry of an object by changing its shape The object modelling of type roof is parametric leaving the ability to the designer to affect the geometry of the object by changing the values of the parameters The designer can alter the value of the centre point offset length offset width D offset length and D offset width parameter The designer can also modify the control points of the B Spline curves reforming the curvature of the respective curves In this way RS MultiCAD allows the designer to shape the object of type roof according to his her requirements 3 5 6 The resultant declarative description The reconstruction phase returns the new declarative description to the declarative phase just when the designer has completed all modifications on the scene RS MultiCAD returns the new declarative description to MultiCAD by submitting the rule set The rule set incorporates all relations and properties that have been declared by the designer The new 92 Chapter 3 declarative description must be enriched perspective the solution generator to produce less solutions on one hand and solutions which are closer to the designer requirements on the other hand The enrichment of the declarative description can be do
116. ir t toutes ces ann es co encadreur et pour avoir accept de faire partie de mon jury Par ailleurs je tiens exprimer Monsieur Georges Miaoulis ma plus sinc re gratitude pour avoir guid mes tudes et m avoir aid envisager de nouvelles perspectives dans ma carri re De m me je remercie Monsieur le Professeur Djamchid GHAZANFARPOUR Directeur du Laboratoire XLIM de l Universit de Limoges de bien vouloir pr sider ce jury et de me faire l honneur d tre pr sent la soutenance Monsieur le Professeur G rard H GRON de l cole d Architecture de Nantes et Monsieur le Professeur Marc DANIEL de l cole Sup rieure d Ing nieurs de Luminy qui ont bien voulu tre rapporteurs et participer au jury je les prie d accepter mes plus sinc res remerciements pour leurs pr cieuses remarques Je tiens aussi remercier Madame Ioanna Ravani et Messieurs George Bardis Ioannis Dragonas Dimitris Makris pour leur collaboration Je remercie galement Madame V ronique M garioti pour sa contribution Enfin j aimerais remercier mes parents pour le soutien qu ils m ont apport dans cette longue aventure qu ont t mes tudes Ces dernieres lignes sont destin es particuli rement ma femme qui m a toujours soutenu malgr les difficult s et surtout mes absences aupr s d elle Je suis particuli rement fier de leurs d dier ce travail de recherche Table of Contents
117. ize operations are treated in the same manner by the algorithm which is presented in Algorithm 3 5 The scale resize operation shares with the move operation the same underlying idea that is based on the calculation of a general bounding box that embodies all related objects The main difference between the scale resize and move operation based on the fact that the dimensions of the bounding box of the object under scale resize are changed while the related objects must simply move to a new position At the time that the general bounding box has been calculated RS MultiCAD system examines if the general bounding box is inside the scene and its position is not occupied by another object which it does not belong to the related objects The position of the all related objects and the position dimensions of their descendants ancestors are updated appropriately implementing the propagation policy Thesis Proposal and Implementation 89 The control module applies the propagation policy and whereas the relations and properties that belong to the rule set are still valid then the new state is legalised The next step is to recalculate the relations and properties of the nodes of the declarative layer in order the declarative layer to reflect the real state of the scene The new relations and properties are added to the collection classes respectively If there is a violation then the stratified representation backtracks to the old state and
118. l step in the product design cycle Differing from the traditional design idea and method reverse engineering technology enables one to start a design from an existing product model by combining computer technology measurement technology and CAD CAM technology Varady 97 In the forward design process the operation sequence usually starts from an idea an abstract model via computer aided design CAD techniques and ends with generation of the geometric model that represents the initial idea In contrast to this conventional design process reverse engineering represents an approach for the new design of a product that may lack an existing CAD model In the process of the product design and research the use of reverse engineering will reduce the production period and costs Reverse engineering technology is not to copy an existing product but to acquire a design concept from an existing physical model and create a complete geometric model and further to optimize the product design According to Peng et al 01 the application areas of a reverse engineering process include e The reverse design either creating a new product from an initial model or feeding a recovered result back to an existing product model to compare and update This is a widely used technique in the tool die and mould making industries e The customized design customized products are worn on our bodies or have prolonged functional contact with the human body There
119. laces the property type along with its declarative value which has been properly calculated to the property collection Figure 3 18 The calculation of spatial relations The extraction module continues applying all stored reflective relations and infers which are valid or not The valid reflective relations are added to the relation collection of the Thesis Proposal and Implementation 85 specific node The extraction module places the reflective relation type along with the object name to the relation collection The extraction module also examines which spatial relations are valid Preparative the system to compute which spatial relations are valid it follows a specific tactic When the system visits a specific node in order to extract the spatial relations it has to compare the geometry of the specific node with the geometry of the rest nodes of the same level of detail which share the same parent Algorithm 3 3 presents the specific tactic which is followed by the extraction module in order to compare the visited node with the rest nodes The specific tactic uses the previous and next labels of each node in order to traverse all appropriate nodes of the same level of detail The extraction module places the spatial relation type along with the related object name to the relation collection of the node Figure 3 18 schematically presents which comparisons have to be made on the geometry of the nodes in order the sys
120. le concepteur peut modifier la g om trie d un objet directement en indiquant de nouvelles valeurs g om triques d une part et d autre part elle il peut changer la topologie de la sc ne en effectuant des modifications sur les objets de la sc ne e La description d clarative de sc ne r sultante peut tre modifi e en adaptant convenablement les exigences du concepteur Le syst me RS MultiCAD maintient un ensemble de r gles o les exigences du concepteur sont gard es en termes de relations entre les objets et les propri t s d objet Le concepteur peut changer l ensemble de r gles en ajoutant ou en supprimant des relations et ou des propri t s Par cons quent en changeant l ensemble de r gles la description d clarative de sc ne r sultante inclut toutes les relations et les propri t s qui appartiennent l ensemble de r gle RS MultiCAD peut tre compar XMultiForms Sellinger 98 puisque les deux syst mes ont t con us pour faire face au couplage d un modeleur d claratif avec un modeleur classique g om trique Les deux syst mes diff rent sur les points suivants 148 Chapitre 5 Le mod le g om trique qui est employ pour l entr e est diff rent dans les deux syst mes Le syst me XMultiFormes re oit un mod le g om trique qui a t produit par le modeleur d claratif MultiFormes Le g n rateur de solutions MultiFormes produit les mod les g om triques qui sont exprim s en termes de p
121. lizes the object on the graphical display The process of visualization continues until all nodes of the geometric layer have been examined 3 5 2 The construction of the stratified representation The import of a geometric model needs a special process The geometric model consists of geometric information of all objects that constitute the scene RS MultiCAD receives the geometric information of the objects and creates the respective nodes of the geometric layer of the stratified representation The system creates one node of the declarative layer for every node of the geometric layer of the stratified representation The nodes of the declarative layer constitute a linked list Figure 3 15 illustrates a typical linked list of the declarative layer A A A A A A PARENT PARENT PARENT PARENT PARENT PARENT Objectl Object2 Object3 Object4 Object5 eA ObjectN PREV IPREV KI PREV PREV PREV x A vx Next N Sax wx CHILDREN CHILDREN CHILDREN CHILDREN CHILDREN CHILDREN v v v v v v Figure 3 15 A typical linked list of the declarative layer It must be pointed out that unlike the internal geometric model of MultiCAD the external geometric model which has been created by another commercial geometric modeller 80 Chapter 3 may not contain any information about the object type and the name In such a case RS MultiCAD set the object
122. lutions to converge to the most recent description Figure 2 6 illustrates the iterative design process within the declarative modelling framework The concept of iterations has been discussed from many researchers Desmontils 95 speaks about the concept of outline Li ge 96 presents the spiral diagram of problem solving Siret 97 organizes in cycles the sequence description generation forms and Colin et al 98 proposes also various working methods within the framework of the iterative design process 2 2 4 Levels of abstraction and levels of detail The design process is considered as decomposable in several successive distinct stages pointing to the initial goals Miaoulis 02 The design process can be viewed as a succession of transformations between descriptions These descriptions can be classified to a representation hierarchy of most abstract to most concrete on levels of abstraction In the framework of the declarative modelling the design process transforms a declarative description into a set of alternative geometric solutions Thus two distinct levels of abstraction are presented the declarative which represents the most abstract and the geometric which represents the most concrete Level of Abstraction Process Evolution Level of Detai Figure 2 7 Evolution of the design process 34 Chapter 2 Generally speaking the design process follows a walk from the general to specific
123. manipulation of the scene modifications along with the construction of the resultant declarative description 58 Chapter 3 3 1 Integration of the two models Geometric and declarative models have useful aspects but are also in some way limited A declarative model corresponds to a set of alternative geometric models and a geometric model corresponds to a set of alternative declarative models Thus the correspondence of the two models is not univocal It must be pointed out that one model complements the other one in a way that many problems of the one model are solved by the other model For this reason the integration of the two models results in an extremely powerful design tool Level of 4 Abstraction High Level Declarative Modelling Intermediate Level Geometric Modelling Low Level Type of Acquired Knowledge Figure 3 1 Type of acquired knowledge according to level of abstraction Figure 3 1 presents the type of the acquired knowledge relative to the level of abstraction On high level of abstraction the valuable knowledge is more declarative than geometric and on low level of abstraction the declarative is less than the geometric specific knowledge On an intermediate level of abstraction the acquired knowledge is a combination of declarative and traditional geometric knowledge Golfinopoulos et al 05 A model in order to become another type of model is gradually transformed into a seque
124. n tant que navigateur idiomatique Le concepteur est m me de changer la topologie de la sc ne choisie et la g om trie des objets qui constituent la sc ne L ensemble de r gles inclut toujours toutes les exigences de concepteur Par cons quent si ces modifications ne violent pas l ensemble de r gles elles m nent une autre solution g om trique qui appartient au m me espace de solution que la solution choisie En outre si les modifications violent l ensemble de r gles et le concepteur souhaite r aliser ces modifications elles m nent un autre espace de solutions et une autre description d clarative de sc ne r sultante Le syst me RS MultiCAD donne au concepteur la possibilit d incorporer un premier mod le g om trique qui est construit par un autre modeleur g om trique classique dans la m thodologie de mod lisation d clarative et pour tirer b n fice de ses avantages D autre part le concepteur re oit du syst me RS MultiCAD une solution g om trique et labore la sc ne pendant le processus de conception d taill avec un autre modeleur classique 5 2 Perspectives de recherche Cette th se se place sur l axe principal de la compr hension et de la gestion s mantique des sc nes dans le cadre de la mod lisation d clarative L approche s mantique choisie vise largir le cycle de conception en mod lisation d clarative fin de pouvoir 150 Chapitre 5 int grer la reconstruction d
125. naissance qui contient la connaissance sp cifique du domaine en d autres termes toutes les informations n cessaires sur le type d objets le type de relations et le type de propri t s d un domaine sp cifique Le concepteur exploite la base de connaissance pendant la phase de description de sc ne afin de d finir les objets les relations et les propri t s appropri s selon la connaissance de domaine sp cifique La r tro conception transforme dans le concept de mod lisation un mod le de niveau d abstraction sp cifique en mod le d un niveau d abstraction plus lev ce qui constitue une tape largement reconnue comme tape cruciale dans le cycle de conception du produit La r tro conception s oppose l ing nierie directe qui est un processus produisant les pi ces physiques partir du mod le g om trique Beaucoup de techniques ont t d velopp es et d crites dans une vaste litt rature sur la r tro conception La m thodologie de la r tro conception a t combin e avec de nombreuses m thodes de mod lisation telles la mod lisation g om trique et la mod lisation par les caract ristiques La reconstruction en trois dimensions 3D est une des branches principales de la r tro conception o un objet physique est transform en mod le g om trique de diverses repr sentations Varady 97 16 Chapitre 1 La r tro conception incorpore un processus de bas niveau pour la reconstruction du mod le g om
126. nce of different levels of abstraction by a sequence of processing steps The Thesis Proposal and Implementation 59 imperativeness of introducing an intermediate model derives from the fact that the nature of a declarative model differs from the nature of a traditional geometric model Our declarative model incorporates a decomposition tree representing the level of details a set of object properties and a set of relations that connects the objects A traditional geometric model incorporates a set of geometric information necessary for representing the objects of the scene Thus the intermediate model consists of declarative and geometric data of the scene that are connected properly Figure 3 2 shows schematically the transformation of a geometric model into declarative via an intermediate model The arrows that connect the different models show the reverse design within the declarative modelling framework Declarative Model Intermediate Model Geometric Model Figure 3 2 The transformation of a geometric model into declarative In the framework of the declarative modelling all geometric models which have been produced from a specific declarative description differ onto the values of the object relations and the values of the object properties The different values of the properties cause an object with a new shape and position on the scene while the different relations cause a new arrangement of the scene
127. ne by influencing the rule set The rule set can be influenced either by the designer or by the system N SET GENERALIZATION FACTOR objectnode node int gf int max tree depth Begin If node children not null Then increase tree depth If tree depth lt gf AND node children children not null OR gf22max tree depth Then add geometric properties of node children to the rule set End If SET GENERALIZATION FACTOR node children gf max tree depth If node next not null Then If tree depth lt gf AND node next children not null OR gf2 2max tree depth Then add geometric properties of node next to the rule set End If SET GENERALIZATION FACTOR node next gf max tree depth Else decrease tree depth return End If Else If node next not null Then If tree depth lt gf AND node next children not null OR gf22max tree depth Then add geometric properties of node next to the rule set End If SET GENERALIZATION FACTOR node next gf max tree depth Else decrease tree depth return End If End Ne Algorithm 3 7 Set the generalization factor The rule set is offered as it is in the manual way if the designer has already changed the rule set by adding relations and properties In the automated way a set of geometric properties are added to the rule set according to the generalization factor since the solutions which are produced by the MultiCAD solution generator differ
128. ng forms the shape of the human model it is hard to capture details of the mannequin and the process of surface fitting is time consuming In Wang et al 03 a feature based approach is presented of building a human model from a point could The noisy points are removed and the orientation of the human model is adjusted A feature based mesh algorithm is applied on the point cloud to construct the mesh surface of a human model The semantic features of the human model are extracted from the surface The advantages of the specific approach are the topology of the human models preserved more details can be included in the feature human model and the algorithm seems more efficient Apart from these in Fisher 04 is presented the contribution of knowledge in reverse engineering problems In particular it is discussed the applicability of domain knowledge of standard shapes and relation ships to solve or improve reverse engineering problems The Related Research Areas 51 problems considered are how to enforce known relationships when data fitting how to extract features even in very noisy data how to get better shape parameter estimates and how to infer data about unseen features Even if the current work focuses on the reconstruction it shows that the applicability of domain knowledge in the general framework of the knowledge based approach plays a significant role in the reverse process The paper explores techniques made at Edinbu
129. nge in the data affects the whole surface while in local methods such a change affects the surface locally In the first category there are methods like the Gordon surface Gordon 69 and polynomial B zier surfaces However if there are a lot of data the degree of the polynomial surface required to fit the data is high which makes the resulting surface unreasonably complicated for further manipulations Therefore designers are more interested in local methods in which a change in the data affects the curve or surface locally Local methods Related Research Areas 23 invoke piecewise triangular polynomials or bipolynomials to define the desired surface Such techniques include piecewise B zier B Splines Rational B Splines and NURBS curves and surfaces Usually there is an initial polygonal or polyhedral approximation of the desired object given in terms of a triangulation Schumaker 93 or a rectangular grid of control points The initial polygon or polyhedron is then smoothed using triangular or rectangular piecewise smooth patches For piecewise B zier one has to enforce smoothness conditions between adjacent patches Gregory 89 De Rose 90 but with the B Spline or NURBS scheme this comes without any special tricks A drawback of rectangular patches is their limited ability to model complex topologies Very often there are n sided holes within a rectangular patch complex Techniques for filling such holes with smooth triangul
130. ntation The insertion of a leaf node is implemented with the specification of the position dimensions object type and its parent while the insertion of an abstract node needs the specification of the object type parents and possible children of the new node In the latter insertion the specification of the position and dimensions are not required since the new abstract node inherits by recalculating the position and dimensions of the bounding box from the positions and dimensions of the specified children S As object Begin If position_of_new_object in site Then If position_of_new_object available Then create node on the declarative layer create node on the geometric layer If parent of new object abstract node Then read which children will be children of the new object set children as children of the new object End If update all ancestors of the new object with new positions dimensions InsertCode success Else InsertCode position_not_available Return End If Else InsertCode out of site Return End If End Algorithm 3 6 Insert operation Algorithm 3 6 presents the insert operation After creating a node on the declarative layer and a node on the geometric layer the RS MultiCAD system performs two main checks in order to determine whereas the position of the new object is placed inside the scene and is not occupied by another object In case the new object creation corresponds to an abstract n
131. o the rule set that results to a reduced solution space according to the solution space of step 1 The designer continues adding relations such as vcorridor adjacent west living room in step 3 and finally in step 4 enriches the rule set by placing the reflective relation living room longer than wide that results to a reduced solution space of 2997 solutions Step No Rulcipet Solutions 1 Initial Set 61072 Initial Set 2 31334 hcorridor adjacent south living room Initial Set 3 hcorridor adjacent south living room 9152 vcorridor adjacent west living room Initial Set hcorridor adjacent south living room 4 2997 vcorridor adjacent west living room living room longer than wide Table 4 11 Manual reduction of the solution space Figure 4 51 presents some geometric solutions generated by the manual way according to steps of Table 4 11 The experimental results of manual reduction of the solution space of the specific example are illustrated in Figure 4 52 where the z axis of the chart is in logarithmic scale The exact numbers of solutions per step are illustrated in Table 4 11 Step 2 Experimental Results 139 Step 3 Step 4 o eS Figure 4 51 Geometric solutions generated by the manual way 70000 60000 50000 40000 30000 No Solutions 20000 10000
132. ode a special manipulation is performed in order the pre specified nodes to become children of the new node The position and dimensions of the ancestors are updated appropriately Finally the extraction module is activated in order to calculate the relations and properties of Thesis Proposal and Implementation 91 the new object and recalculate the relations and properties of the rest objects It must be pointed out that the insertion of a new object is not compared with rule set since the relations and the properties of the stratified representation remain the same for the existing objects The update of the stratified representation occurs only for the new inserted object 3 5 5 4 Deletion operation The deletion operation allows the designer to delete an existing object of the scene The object under deletion may correspond to a leaf node or an abstract node on the declarative layer of the stratified representation The deletion of a leaf node is implemented by erasing the relative nodes from the geometric and the declarative layer of the stratified representation The deletion of an abstract node causes the collapse of the sub tree where the object under deletion is root of the declarative layer and the deletion of all respective nodes of the geometric layer The stratified representation is updated in order to reflect the new state of the scene after the deletion and the extraction module is activated in order to recalculate the relat
133. odification is applied Figure 4 21 presents the result 10 0180 12 4366 0 0000 Figure 4 21 Delete an object Experimental Results 113 The deletion of a leaf node causes the deletion of the specific node while the deletion of an abstract node causes the collapse of the sub tree where the node is root In such a case all descendants are deleted and all relevant relations and properties that belong to the rule set are erased 4 2 1 6 Change extra geometric characteristics In case the designer changes the extra geometric characteristics of the object roof_16 causes changes inside the bounding box of the object Changing the geometric characteristics D offset length D offset width and all relevant B Splines with new values alters the geometry of the object roof_16 The position and the dimensions of the bounding box remain the same as before the modification The result is illustrated in Figure 4 22 MRS MultiCAD fel F e Scene Change Return Opens OEM MIE gt a buiding 2 bvrgroom_9 playroom 6 Vp E 10 8977 6 8647 0 0000 Figure 4 22 Change extra geometric characteristics 4 2 1 7 Change the rule set In case the designer wants to change the relations properties that belong to the rule set by double clicking on the relation property can add the specific relation property to the rule set or remove an already relation property from th
134. of declarative and geometric information Declarative information can be summarized into object set and rule set Geometric information deals with the geometry of each object that constitutes the scene The control mechanism is event driven and is responsible for the stratified representation to ensure the correct transition from one state to another It handles the designer scene modifications examining their semantic correctness and properly updates the stratified representation by propagating the changes in a mixed way 64 Chapter 3 Stratified Representation Object Rule Geometric 4 gt pL Set Set Model dxf etc ae Knowledge DB Extraction Control MPOT Export module module mod le a Multimedia DB DB gt Figure 3 6 Detailed system architecture of RS MultiCAD system GUI 3D Editor Explanation module RS MultiCAD The explanation module provides valuable information about the system reasoning in cases where a scene modification violates the rule set Finally the RS MultiCAD system incorporates a graphical user interface with a 3D editor in order to visualize the solutions and graphically receive the designer requests Figure 3 6 illustrates the detailed RS MultiCAD system architecture The inner operation cycle of RS MultiCAD incorporates all necessary mechanisms for converting a geometric model in
135. of resize flat 7 Figure 4 13 Resize storage 12 to a new height Figure 4 14 Position not available Figure 4 15 Scale aux building Figure 4 16 Position not available Figure 4 17 Object insertion Figure 4 18 Further objects insertion Figure 4 19 Insert an abstract object Figure 4 20 The result of the insertion Figure 4 21 Delete an object Figure 4 22 Change extra geometric characteristics Figure 4 23 Rule set enhancement Figure 4 24 Save the declarative description Figure 4 25 Save the geometric solution Figure 4 26 Reduce the solution space Figure 4 27 Experimental results of automated reduction of the solution space Figure 4 28 Geometric solutions generated by the automated way Figure 4 29 Experimental results of manual reduction of the solution space Figure 4 30 Geometric solutions generated by the manual way Figure 4 31 An external geometric model Figure 4 32 Import of an external geometric model Figure 4 33 Type declaration and object rename 106 107 107 108 109 109 110 111 111 112 112 113 115 116 117 118 119 120 121 122 123 123 124 8 List of Figures Figure 4 34 Insert an abstract object of type house 125 Figure 4 35 Insert an object of type roof 125 Figure 4 36 Change extra geometric characteristics 126
136. on the position and dimensions of the object that constitute the scene The main idea of the automated way is to Thesis Proposal and Implementation 93 lock the position and dimensions of some objects and leave the solution generator to produce solutions about the rest objects Algorithm 3 7 illustrates the main core of the algorithm that handles which nodes of the decomposition tree will provide their geometric properties to the rule set For this purpose the pre order traversal is used which traverses the left sub tree if any and then traverses the right sub tree if any The algorithm starts from the root of the decomposition tree and examines whereas any child exists If so the control passes to that node which is the first child and examines if the depth of the tree at this point is less than the generalization factor and if there is any descendant In case of the checks are valid then the geometric properties of the node are added to the rule set The algorithm is recursive and continues by calling the children of the node As soon as the current node is a leaf node of the decomposition tree the algorithm examines whereas any brother exists If so then the control passes to the node which is the nearest brother and examines if the depth of the tree at this point is less than the generalization factor and if there is any descendant If so then the pure geometric properties of that node are added to the rule set and the algorithm
137. onnaissance du syst me MultiCAD incorpore la connaissance sp cifique de domaine relative au type d objets de rapports et de propri t s La connaissance fait r f rence la conception architecturale des b timents 1 2 Les objectifs de la recherche Le but principal de la th se est de transformer un mod le g om trique en mod le d claratif dans le cadre de la mod lisation d clarative pendant la premi re partie du processus de conception Afin d atteindre ce but une approche de r tro conception bas e sur la connaissance a t d velopp e dans le but de r aliser le couplage d un modeleur g om trique classique un modeleur d claratif L approche est plac e dans le cadre de la mod lisation d clarative et de la r tro conception Introduction 17 L approche de r tro conception bas e sur la connaissance implique le d veloppement d un syst me intelligent de prototype qui fonctionne dans l architecture MultiCAD pour la conception architecturale des b timents MultiCAD re oit une description d clarative des conditions de b timent et produit un ensemble de mod les g om triques alternatifs Le concepteur choisit une repr sentation g om trique d sir e Le syst me intelligent de prototype comprend s mantiquement la repr sentation g om trique s lectionn e et permet au concepteur d effectuer des modifications g om triques et topologiques sur la sc ne sp cifique Le syst me v rifie si les modifica
138. orms VoluFormes consists of two modules Voluboites and Voluscenes The Voluboites module permits the user to define the boxes where the spatial control takes place The definition of the boxes is performed by using natural like language The Voluscenes module allows using growth mechanisms applied to elementary germs and creating forms taking into consideration the spatial control boxes The generation takes place in an incremental manner Each box is placed in the space and if the user does not like the proposed box and placement another solution is generated Once the current box is placed in the space the same process applies to the next box Figure 2 2 presents the form growth of VoluFormes Figure 2 2 Example of form growth by VoluFormes M gaFormes In Poulet et al 96 is presented a modeller for the modelling of megalithic monuments The objective of this modeller is to be able to rebuild megalithic monuments starting from a declaratory model and then visit them in a virtual way Dem ons In Kwaiter et al 97 a declarative modeller is presented for object placement in 3D scene surface and provides an object library and space constraints for defining the positions of the objects Demons generate one solution per description The modeller uses a multi modal interface allowing descriptions by means of the voice the keyboard natural language a data glove or 3D captors informing the system of the user s position The Rel
139. os et al 06 The import export module is responsible for the communication with the databases supporting the input and output of geometric solution the output of a new declarative description which comes from designer modifications and finally the import and export of a geometrical model of different file format DXF file format The latter enhances the interoperability of the system since the designer can either import a design from another CAD system and produce alternative solutions or export the solution to other CAD system and continue the design process For further information on DXF file format see Appendix B The extraction module applies all domain specific relation and property types see Appendix A in order to extract all valid relations and properties of the objects from a selected solution The extraction module is domain independent and facilitates the extension of knowledge and concept database since it parses the available knowledge from the databases It must be pointed out that only the knowledge base is used for the extraction of the appropriate properties and relations from the scene and the concept database will contain all necessary concept representations The control module incorporates all necessary mechanisms for building manipulating and updating the stratified representation The stratified representation is dynamic and constructed from the designer selected solution with a top down approach and mainly consists
140. ossible There is no guarantee that the CAD model will be acceptably close to the sculpted model Reverse engineering provides a solution to this problem because the physical model is the source of information for the CAD model Another reason for reverse engineering is to compress product development time Rapid product development refers to recently developed technologies and techniques that assist manufacturers and designers in meeting the demands of reduced product development time By using reverse engineering a three dimensional product or model can be quickly captured in digital form re modelled and exported for rapid prototyping tooling or rapid manufacturing 2 4 1 Reverse engineering in scene modelling As mentioned before the design process can be viewed as a successive transformation between models These models can be classified into a representation hierarchy of most general to most specific according to the levels of abstraction Usually we start the design process indicating a conceptual model which is transformed into specific model Within the framework of MultiCAD several scene model types exist according to levels of abstraction Miaoulis 02 Related Research Areas 45 e Abstract conceptual models The abstract models are scene models necessarily generic and can give a series models of lower level of abstraction The type of these models can be internal declarative representations or documents in natural language
141. paradigm associated to the declarative modelling systems Poster in 31A 1998 Conference Limoges April 1998 Mortenson M E Geometric Modelling John Wiley amp Sons 1985 Pahl G Beitz W Engineering Design A Systematic Approach 2 edition Springer Verlag London 1996 Peng Q Loftus M Using image processing based on neural networks in reverse engineering International Journal of Machine Tools amp Manufacture 41 2001 625 640 Petitjean S A survey of methods for recovering quadrics in triangle meshes ACM Comput Surveys 2002 34 2 211 62 Plemenos D A contribution to study and development of scene modelling generation and display techniques the MultiFormes project Professoral dissertation Nantes France November 1991 Plemenos D Declarative modelling by hierarchical decomposition The actual state of the MultiFormes project International Conference GraphicCon 795 St Petersburg 158 Bibliography Plemenos et al 02 Plemenos et al 97 Poulet 94 Poulet et al 96 Prabhakar et al 92 Ravani et al 04 Ravani et al 03 Requicha 80 Russia July 1995 Plemenos D Miaoulis G Vassilas N 2002 Machine learning for a general purpose declarative scene modeller International Conference GraphiCon 2002 Nizhny Novgorod Russia Plemenos D Tamine K 1997 Increasing the efficiency of declarative mod
142. pproaches permit the designer to describe the desired scene in an abstract way Besides both offer constraint based techniques through parameters in feature based modelling and through property specification in declarative modelling Another similarity is the object oriented nature where the designer approaches the design itself through objects instead of handling geometric primitives One the other hand feature based has differences with declarative modelling A boundary model needs all relevant geometric information in order to be constructed while declarative modelling can handle the imprecise information In addition declarative modelling produces a set of alternative solutions while feature based modelling produces just one geometric solution Feature based systems are usually history based since they keep track of the designer operations Changing the order of the designer operations may lead to different boundary model Declarative modelling incorporates a solution generator which produces solutions according to the property specifications despite of the order 2 4 Reverse engineering Engineering is the process involved in designing manufacturing constructing and maintaining of products systems and structures At a higher level there are two types of engineering forward engineering and reverse engineering Generally speaking reverse engineering is the process of taking something a device an electrical component a software
143. program et cetera apart and analyzing its workings in detail usually with the intention to construct a new device or program that does the same thing without actually copying anything from the original In other words reverse engineering is the process of analyzing a subject system to 1 identify the system s components and their 44 Chapter 2 interrelationships and ii create representations of the system in another form or a higher level of abstraction Chikofsky et al 90 Forward engineering is the traditional process of moving from high level abstractions and logical implementation independent designs to the physical implementation of a system Chikofsky et al 90 Reengineering also known as renovation and reclamation is the examination and alteration of a subject system to reconstitute it in a new form and the subsequent implementation of the new form Reengineering is the modification of a system that takes place after it has been reverse engineered generally to add new functionality Reverse engineering is very common in such diverse fields as software engineering entertainment automotive consumer products microchips chemicals electronics and mechanical designs In some situations designers give a shape to their ideas by using clay plaster wood or foam rubber but a CAD model is needed to enable the manufacturing of the part As products become more organic in shape designing in CAD may be challenging or imp
144. re complex shapes can be modelled with surface modelling than with wire frames By definition a solid is a 3D object with a well defined inside and outside separated by a two dimensional 2D boundary Many techniques have been developed for generating and storing geometric models which are represented as solids such as Constructive Solid Geometry CSG Boundary representation B rep octrees and others Requicha 80 CSG models use geometric primitives which are attractive for the creation of feature primitives but do not contain sufficient structured or detailed information about the faces edges and vertices of components This kind of information which is essential for reasoning about the geometry and for tolerance definition is explicitly represented in B rep models From the point of view of the techniques used for geometric modelling purposes there are two basic approaches transfinite interpolation and discrete approximation and interpolation In transfinite interpolation a surface is constructed such that it goes through a given collection of curves Cross sectional design is an example of a method that falls into this category Woodward 87 In discrete approximation interpolation a surface that approximates interpolates a given set of data points is constructed Based on the manner in which a change in the data affects the curve or surface to be constructed we can categorise methods into global and local In global methods a cha
145. re geometric panel presents the 96 Chapter 4 basic geometric characteristics of the selected object and the extra geometric panel presents the additional geometric characteristics of the current selected object All panels provide scroll bars in order to hospitalize large scenes with many objects RS MultiCAD File Scene Change Return Options 0280 03090 0 9 site building 2 living room_5 play room_6 roof_13 roof_14 building 3 flat kitchen 8 bathroom 8 bedroom 10 foot building 4 garage 11 Object flat 7 flat 7 flat 7 Property Value Is Long high Is Wide no no Reflexive Relation Longer Than High I Longer Than Wide Relations ON GeoProperties OFF Declarative 13 2864 11 1854 0 0000 ees eis living room 5 play room 6 L Toolbar roof_16 storage 12 bedroom 10 bathroom 9 roof 14 garage 11 roof 13 Extra Geometric Panel D necs li Graphical Display Pure Geometric Current Solution 1 Geo Property Value Position X Is Position Y Is Position Z Is Length Is Width Is Height Is ae B Color Type B 220 57 57 roof El BaseWeights Int32 Array 0 n 2 3 DoffsetLengt 0 Doffsetwidth 0 OffsetLength 0 Offsetwidth 0 7 E Splinet Figure 4 1 The working space of RS MultiCAD Int32 Array 0 100 1 50 E Th
146. recalculating and updating its brothers and continues to ancestors until the root node of the decomposition tree On the left hand side of the figure 3 11 is shown schematically that a modification on a leaf node shaded area affects its brothers and continues to ancestors shaded area Whenever a modification occurs on an abstract node then the propagation starts from recalculating and updating its children and brothers and continues to children of brothers and to ancestors until the root node of the decomposition tree On the right hand side of the figure 3 11 is shown schematically that a modification on an abstract node shaded area affects first of all its children then its brothers children and continues to ancestors shaded area Figure 3 11 The propagation policy Thesis Proposal and Implementation 75 Let us suppose that an object of type house is decomposed into an object of type bedroom and an object of type kitchen which are related with a relation of type adjacent north A possible move taking into consideration the aforementioned relation of the object type kitchen causes the object of type bedroom to change its initial position and afterwards causes the object of type house to change its position and dimensions respectively At last a possible move of the object type house causes the objects of type be
147. ree main modules Golfinopoulos et al 05 Our geometric model consists of information about the types of the objects and the geometric aspects of the objects The input file provides the types of the objects along with the position and dimensions of the bounding box which specify every object on the scene Geometric Declarative Model Model Stratified Representation E SS Methods Control o Mechanism Knowledge amp Concept Figure 3 5 General architecture of RS MultiCAD system Generally speaking the methods component consists of procedures and functions for extracting features and relations from the geometric model The knowledge amp concept component involves the knowledge database and concept database along with the mechanisms for retrieving the knowledge for the database The control mechanism component incorporates all necessary mechanisms for building handling and manipulating the Thesis Proposal and Implementation 63 intermediate model whenever the designer tries to alter the objects geometry of the scene Figure 3 5 illustrates the general architecture of the RS MultiCAD system The RS MultiCAD knowledge based system incorporates architectural domain specific knowledge for constructing buildings The system architecture is modular giving the possibility to further extensions The system is based on five main modules from a high level of detail Golfinopoul
148. researchers have worked on the aforementioned solver Tamine 95 Plemenos et al 97 Bonnefoi 99 Figure 2 9 illustrates different solutions of MultiFormes Residence NX IN IN PK N o XI Xx WM ER ER ER NENEN Figure 2 9 Solutions of MultiFormes Related Research Areas 37 MultiFormes has been designed to produce all possible geometric solutions that satisfy the constraints which have been declared by the designer in terms of properties Therefore the predefined properties operate as constraints and reduce the range of the values that the starting position and the size of the bounding boxes can take The set of different geometric solutions is produced from an exhaustive exploration of all permitted values that can be applied on the starting position and the size of each bounding box within a specific workspace Besides the number of the predefined properties along with the complexity of the described scene affect the generation time of the geometric solutions Special suggestions for improvement of the description and generation phase of MultiFormes take place in Bonnefoi 99 and Ruchaud 01 Fribault in Fribault 98 Fribault 04 proposes and implements an information system associated with a declarative modeller for the assistance of habitation edifices The necessary properties are defined for describing a building along with the assembly rule utilised in the architectural design According to the declarative
149. rge de l exploitation de la base de connaissance du modeleur d claratif de MultiCAD Conclusions et Perspectives 147 La base de connaissance actuelle de MultiCAD contient toute la connaissance appropri e sur des types d objets des types de relations et des types de propri t s qui sont impliqu es dans la conception de b timents En outre le syst me de RS MultiCAD a t con u d une mani re modulaire afin de pouvoir comprendre n importe quelle sc ne ind pendamment de la conception e Le processus d claratif it ratif devient int gralement support par ordinateur Le syst me RS MultiCAD met en application la nature it rative de la mod lisation d clarative en automatisant le processus Une nouvelle description d clarative merge chaque fois que RS MultiCAD re oit un mod le g om trique et fournit la description d clarative de sc ne de MultiCAD Par cons quent le concepteur lib re du souci de red finir la description d clarative de sc ne pour l it ration suivante e La sc ne peut tre modifi e pendant la phase de reconstruction Le syst me RS MultiCAD permet au concepteur de faire toutes les modifications n cessaires sur une sc ne choisie avant la construction de la nouvelle description d clarative de sc ne pour que le concepteur change ses conditions Les modifications qui peuvent tre r alis es sont class es par cat gorie selon la mani re o le concepteur informe le syst me Par cons quent
150. rgh University to improve reverse engineering of objects from three dimensional 3D point data sets by applying constraints on feature relationships in manufactured objects and buildings in order to improve the recovery of object models by applying general shape knowledge for recovery even when data is very noisy sparse or incomplete Many of these recovery problems require discovery of shape and position parameters that satisfy the knowledge derived constraints Evolutionary search methods can be used to do this search effectively The research from the University of Utah Thompson et al 99 de St Germain et al 97 who have also been investigating constrained reconstruction of parts from 3D data sets particularly parts with pocket profiles They categorized the types of engineering knowledge as domain specific and pragmatic and functional constraints They exploit this knowledge to select surface types and manufacturing actions Thus with some user assistance planar features that bound pockets are found The contour that is swept to form the pocket can then be found automatically Shape and positional constraints are represented and solved in a manner similar to Fisher 04 The research from the University of Cardiff Benk et al 02 Benk et al 01 exploits designed in relationships to improve reconstruction In their case a much larger set of relationships was explored and the constraints arising from the relationships were
151. ription 134 4 3 2 2 Save the geometric solution 135 4 3 3 Reduction of the solution space 136 4 3 3 1 Automated way 136 4 3 3 2 Manual way 137 4 4 DISCUSSION 140 CHAPITRE 5 CONCLUSIONS ET PERSPECTIVES 143 5 1 REMARQUES DE CONCLUSION 146 5 2 PERSPECTIVES DE RECHERCHE 149 BIBLIOGRAPHY 151 APPENDIX A RELATIONS AND PROPERTIES 163 A 1 RELATIONS 163 A 2 PROPERTIES 169 APPENDIX B DXF FORMAT 171 APPENDIX C THE TRADITIONAL GEOMETRIC MODELLER 175 List of Figures Figure 2 1 Example of polyhedron generated by PolyFormes Figure 2 2 Example of box arrangement and form growth by VoluFormes Figure 2 3 Scenes created by Dem ons Figure 2 4 Examples of generated buildings by BatiMan Figure 2 5 The declarative conception cycle Figure 2 6 The iterative design process Figure 2 7 Evolution of the design process Figure 2 8 A typical example of a decomposition tree Figure 2 9 Solutions of MultiFormes Figure 2 10 The working space of MultiCAD Figure 2 11 A boundary model Figure 2 12 The transformation of models Figure 2 13 Models according to the level of abstraction Figure 3 1 Type of acquired knowledge according to level of abstraction Figure 3 2 The transformation of a geometric model into declarative Figure 3 3 The new declarative conception cycle Figure 3 4 Extended design methodology and modelling levels Figure 3 5 General architecture of RS MultiCAD system Figure 3 6
152. rphology 78 Chapter 3 The meaning of the parameters of the roof primitive geometric shape is shown schematically in Figure 3 13 The designer can set the values of the centre point offset length offset width D offset length D offset width and also the control points of the B Spline curves that control the endpoint tangent vectors The value of the control points varies from 1 to 100 as it is shown in Figure 3 14 Figure 3 14 Control points of B Spline curves The construction of object type roof is based on controlling the complex geometric shape by eight cubic B Splines For simplicity each B Spline s projection on a plane is manipulated Each B Spline is defined by five points The first point and last are the corresponding start and end point of the B Spline and their position is relative to the position and size of the object roof The remaining three control points are used to define the B Spline shape as Figure 3 14 shows These points cannot freely move on the plane in order to reduce the complexity of the final object The first point can be moved only along the Y axis and the X coordinate is always zero It must be pointed out that the coordinates are relative to the B Splines plane projection and not in world coordinate system The second point can only be moved along the plane s diagonal The Y coordinate of the last point equals to the height of the plane which is the same with the heigh
153. s by the human designer and finally the GGM system produces a large set of designs a specialised browsing system allows the designer to search the set of generated designs in a directed manner A typical modelling session using the CCAD system proceeds as follows e The designer uses the traditional geometric modelling TGM system to generate a nascent design to be used in the first iteration of automated modelling e The designer then uses a dialog with the GGM system to define the constraints to be used during the generation process e The GGM system then instantiates all valid geometric designs These designs are presented as icon like buttons in a large screen area and the designer can get a large image of a design by clicking on the corresponding button e The designer then selects a set of promising designs using the browsing system Related Research Areas 27 e The selected designs are then returned to GGM system and the last four steps are repeated until the desired design has been constructed Many declarative modellers have been germinated in France most of them are limited to very restricted domains e PolyFormes In Martin P and D 88 Martin P and D 89 PolyFormes is a specialised declarative modeller which is based on regular and semi regular polyhedra that can be very complex The goal of PolyFormes is to generate all regular and semi regular polyhedra according to user s requests which are express
154. s illustrated in Figure 4 45 M RS MultiCAD F e Scene Change Renn Opeens sigieeioigoie een elo sleine Coke 7To 155 170 Tye Condor AN M 2596 11 5922 0 0000 Relations ON GecProgerties OFF Figure 4 45 Resize vcorridor to a new length In case the designer scales the object house_10 by 10 the modification is canceled since the property Height_is 3 belongs to the rule set and is violated The result is illustrated in Figure 4 46 134 Chapter 4 RS MultiCAD _elx Figure 4 46 Violation of scaling the house_10 4 3 2 Model storage 4 3 2 1 Save the declarative description Type aquedtien ter hp S otz ci 40 vasteet2 4 42 vas psper 44 vas papon 45 vas paper 46 fina 47 finDXF 8588828285585 550 bedroom 10 551 comdor 11 552 comdor 12 562 site 563 house 564 Kitchen 82853828889833893238 822288 88 RFjS 38353939988 BE REESRERPHBSBSEESEEEEZE EIGENEEIEBIEIEL ELE ET ELE EL ET E EL B EL E ELE CZ LEE ELE ELE SETEEPECEEETETTEAS Record 10 f 1 CPPS or 523 Figure 4 47 Save the declarative description Experimental Results 135 As soon as the designer has completed all modifications on the scene saves the new declarative description in the MultiCAD database Figure 4 47 illustrates the respective records that are stored of the above example in the Scene Database of MultiCAD 4 3 2 2 Save the geometric solution
155. se case diagram The cycle starts with a declarative description which produces a set of geometric solutions The solutions are visualized and the designer selects the most desirable geometric solution In the reconstruction phase the designer can edit the geometric solution a new declarative description is created which Thesis Proposal and Implementation 61 contains the changes and a new cycle starts resulting to more promising solutions The iterative process aims to produce scenes which meet the designer requirements after refinement The designer can proclaim his requirements declaratively and geometrically Due to the introduction of the reconstruction phase in the declarative conception cycle the design methodology is extended and presented in the below sub section 3 3 Extended design methodology The design methodology of the declarative modelling extends in order to include the reconstruction phase The extended design methodology Golfinopoulos et al 06 starts with the description of the desired scene in terms of objects relations and properties through an interface A rule set and object set are built representing the designer requirements Description Phase Reconstruction Phase Type of Type of Type of Object Rule Import Export Objects Properties Relations Set Set Model v vy v y Declarative Stratified Modelling Modelling PAS
156. se engineering and declarative modelling Reverse engineering in the declarative modelling framework acquires a geometric solution which can be modified by the designer and results a new declarative description to the next iteration of the declarative conception cycle The XMultiFormes project Sellinger 98 Sellinger 95 is a previous work that tries to integrate the two modellers by using a special interface system to ensure that there is full and complete transfer of information between the declarative and a traditional geometric modeller This system is composed of four sub processes each of which is responsible for one aspect of the information transfer The geometric convection process translates the geometric representation generated by MultiFormes into one that is more suited to interactive modelling The principal geometrical entity used by solution generator of MultiFormes is a closed parallelepiped which is formed by six connected surfaces of B zier and is converted into three linked lists Sellinger et al 97 At the lowest level is a list of vertices which are used to implement a set of geometric primitives the second level of representation At the third level is the compound primitive of MultiFormes At the highest level is the object entity which is constructed from either a set of primitives or other objects The labelling system is responsible for capturing non geometric information which is implied in the declarativ
157. sed in terms of a set of faces and edges The graph based method discussed by Little et al 98 syntax based method proposed by Li 88 rule based method discussed by Henderson 84 and neural network method raised by Prabhakar et al 92 are examples of this category On the contrary the features and object description are defined in terms of primitives in the volume recognition category Typical examples are the convex hull algorithm by Kim 92 hint based reasoning method by Han et al 98 and curvature region approach by Sonthi et al 98 Although many different methods are proposed to recognize the features from an object description only regular shaped objects can be handled Little et al 98 Sonthi et al 98 In Au et al 99 is discussed the issues of applying feature technology to reverse engineering technology of a mannequin According to that the feature model of a mannequin consists of the major features of the torso for garment design and the features are recognised from the point cloud by comparing it with a generic feature model Association is set up between the point cloud and the mannequin feature Fitting the generic model to the point cloud yields the mannequin feature model of a specific person This is achieved by optimizing the distance between the point cloud and the feature surface subject to the continuity requirements However the task of matching the critical points is done manually Since surface fitti
158. semantic feature modelling PhD Thesis Delft University of Technology Netherlands 1999 Bonnefoi P Techniques de satisfaction de contraintes pour la mod lisation d clarative Application a la g n ration concurrente de sc nes PhD Thesis University of Limoges France 1999 Bonnefoi P F Plemenos D Constraint satisfaction techniques 152 Bibliography Champciaux 98 Charrot 84 Chauvat 95 Chauvat et al 94 Chikofsky et al 90 Chivate et al 95 Colin 88 Colin 90 Colin et al 97 for declarative scene modeling by hierarchical decomposition 3IA 2002 Limoges France Champciaux L Introduction de techniques d apprentissage en mod lisation d clarative Th se de doctorat Nantes France Juin 1998 Charrot P Gregory JA A pentagonal surface patch for computer aided geometric design Computer Aided Geometric Design 1984 1 87 94 Chauvat D Cr ation de sc nes par contr le spatial et m canismes de croissance Revue internationale de CFAO volume 10 no 4 1995 Chauvat D Le projet VoluFormes un exemple de mod lisation d clarative avec contr le spatial Th se de doctorat Nantes D cembre 1994 Elliot J Chikofsky and James H Cross II Reverse engineering and design recovery A taxonomy IEEE Software pages 13 17 January 1990 Chivate PN Jablokow AG Review of surface representations and fitting for rev
159. soning for feature recognition status report Computer Aided Design 1998 30 13 1003 7 Henderson MR Extraction of feature information from three dimensional computer aided design data PhD dissertation Purdue University 1984 Kim YS Recognition of form features using convex decomposition Computer Aided Design 1992 24 9 461 76 Kochhar S Cooperative Computer Aided Design A paradigm for automating the design and modeling of graphical objects TS 18 90 Harvard University Cambridge MA July 1990 Kochhar S CCAD a paradigm for human computer cooperation in design IEEE Computer Graphicas and Bibliography 155 Kwaiter et al 97 La Greca et al 04 La Greca et al 06 Le Goff 90 Le Roux et al 04 Li 88 Li ge 96 Lina et al 05 Applications May 1994 Kwaiter G Gaildrat V Caubet R Demos a high level declarative modeller for modelling objects with constraints Proceedings of Compugraphics 96 Portugal pp 211 219 La Greca R Daniel M Declarative approach to NURBS surface design from semantic to geometric models 31A 2004 Conference Limoges France La Greca R Daniel M A declarative system to design preliminary surfaces WSCG 06 Plzen Czech Republic February 2006 Le Goff D Mod lisation d clarative et morphologie urbaine Rapport de DEA Nantes Octobre 1990 Le Roux O Gaildrat V Caubet R
160. ss sectional design of B Spline surfaces Computers and Graphics 1987 11 2 193 201 Zhang Yu Research into the engineering application of reverse engineering technology Journal of Materials Processing Technology 139 2003 472 475 Appendix Relations and Properties A 1 Relations Adjacent North Object A Adjacent North Object B Moab sx 5X 4A Z HS S7 Hox D Za Zn VB Adjacent South X Object A Adjacent South Object B X PX SY Rp A Z HSZQEZ HA D S Za Zg Y Y W 164 Appendix A Adjacent West X Object A Adjacent West Object B Y W lt Y SY W Z H lt Z lt Z H A X X L Adjacent East X Object A Adjacent East Object B Y W XY XY W Z H lt Z lt 5Z H X X L Adjacent Over X Object A Adjacent Over Object B X L EX Xy L4 A Y W XY SY W Z Z H Relations and Properties 165 Adjacent Under Equal Length Equal Width X Object A Adjacent Under Object B X L SX SX L Y W SY SY W A Z Z H J A Z p gt 4 gm R Y Object A Equal Length Object B L L J X Object A Equal Width Object B W W 166 Appendix A Equal Height X Y RP EX Object A Equal Height Object B vet H H W T S Longer Than Shorter Than X a X Object A Longer Than Object B
161. styles par algorithmes g n tiques Application la cr ation architecturale PhD Thesis University of Limoges France 2005 Makris D Ravani I Miaoulis G Skourlas C Plemenos D Towards a domain specific knowledge intelligence information system for Computer Aided Architectural Design 31A 2003 Conference Limoges France 2003 Martin P and D Catalogue de poly dres Report LIST 89 03 June 1989 Martin P et D An expert system for polyhedra modeling Eurographics 88 Nice France September pp 221 232 Miaoulis G Contribution l tude des Syst mes d Information Multim dia et Intelligent d di s la Conception D clarative Assist e par l Ordinateur Le projet MultiCAD PhD Thesis University of Limoges France 2002 Bibliography 157 Miaoulis et al 00 Miaoulis et al 96 Miaoulis et al 98 Mortenson 85 Pahl et al 96 Peng et al 01 Petitjean 02 Plemenos 91 Plemenos 95 Miaoulis G Plemenos D Skourlas C MultiCAD Database Toward a unified data and knowledge representation for database scene modeling 31A 2000 Conference Limoges France 2000 Miaoulis G Plemenos D Propositions pour un syst me d information multim dia intelligent d di la CAO Le projet MultiCAD Rapport de recherche MSI 96 03 Limoges 1996 Miaoulis G Plemenos D Basic elements of a design process and information system
162. sults 127 ML mie GeoPwpedy Vain Position X ls 0 Postion Y ls 0 Postion Z 3 Length Ir Width li 10 Height la EN a Coker 2007 200 100 a Tyee root E D aseWesii IMIA Anay bl ni Es Ri n ni 3 Dofftet eng 0 Doftzefweth D OlfseiLersgh D Ottsetwith 0 B Spine IIA Array n x m 100 2 100 B Soie Intl Array mi n 100 t2 100 d Spine IMIA Array 10 EJ z ntx 4 3629 13 3063 0 0000 m 100 z Figure 4 37 The deletion of the object roof 11 4 3 1 6 Change the rule set Initially the rule set is empty since there is no declarative description In case the designer wants to change the rule set by double clicking on the relation property can add the specific relation property to the rule set The properties are presented in the table 4 9 Object Property Value Is long Medium Kitchen Is wide Low Is long Low Bathroom Is wide Low Is long Medium Office Is wide Medium ong Is_long High Living room Is wide High Is long Low Dining room Is wide Medium Is long Medium Bedroom Is wide Low 128 Chapter 4 VCorridor Is_wide Medium HCorridor Is_long Low Kitchen Height_is 3 Table 4 9 Properties Furthermore since the rule set is empty the designer adds relations to the rule set in order to specify how the objects are related to each other In other words the designer defines
163. surface or a sculptured surface In these cases reverse engineering is an efficient approach to significantly reduce the product development cycle Zhang 03 It is often used in cases such as the following e Where a prototype of the final product has been modelled manually and therefore no CAD model of the prototype exists e g clay model in automotive industry e Where a CAD is introduced in a company and all existing products must be modelled in order to have a fully digital archive Particularly the CAD model of a complex shaped part is modelled because it is difficult to create its CAD model directly e Where complex shaped parts must be inspected and therefore the reverse engineering model created will be compared to an existing CAD model In medical engineering a representative example of reverse engineering is the customized artificial joint design Lina et al 05 where in order to meet the requirements and to reduce the production cycle and cost a method is presented to generate the complex surface of an artificial knee joint by co ordinate measuring machine from the normative prosthesis and form the model data base The method gets the better data points among point cloud data and then the free form surfaces are constructed from the point cloud data using the reverse engineering software Surfacer The solid CAD model of the artificial knee joint is created from the surfaces by extension intersection These models forme
164. t be properly updated in order to reflect the real state of the scene RS MultiCAD follows the generate and test method and provides two inference options according to designer modification which may or may not be activated e Check the modification according to the rule set A modification is valid as long as none relation or property of the rule set is violated otherwise the modification is invalid and it is cancelled If the designer decides not to check the modifications according to the rule set the control module performs a set of mandatory conditions ensuring the validity of the scene such as none overlapping objects of the same level of abstraction none object exceeding the overall scene limits et cetera e Add pure geometric properties to the rule set that are inferred from the modifications If the designer moves an object to a new position pure geometric properties relative to move are added to the rule set The control module properly propagates the modification by updating the geometric layer of the stratified representation and activating the extraction module in order to recalculate all valid relations and properties The control module assures that the transaction from one state to another one is valid since all relations properties of the rule set are not violated and the changes are accepted while the new state of the stratified representation is valid Otherwise the explanation module is activated in order to recor
165. t of the object roof and can be moved only along X axis If the object roof has the D offset length and D offset width properties set then the B Splines 1 3 5 7 are duplicated as shown in Figure 3 13 Finally for each B Spline the control points are transformed into world coordinate system to form the frame of the object roof Perspective to construct the final object every B Spline is divided into equal sections and a vertex face list are created VectorDraw handles the polyface drawing once Thesis Proposal and Implementation 79 it is added into the entities collection Generally speaking in order to represent other objects of type building office et cetera where geometric shape is the parallelepiped a solid box is used It is not necessary to construct a three dimensional box using a polyface object since VectorDraw Viewer component provides a method that constructs a polyface box given its position and dimensions The visualization of a scene is based on the nodes of the geometric layer of the stratified representation where all geometric information is captured in the pure geometric properties and the extra geometric characteristics of the objects For every node the system checks whether the corresponding node of the declarative layer is a leaf or abstract Since the node has none child RS MultiCAD obtains the geometric information of the corresponding node of the geometric layer and visua
166. tem to extract the spatial relations of the specific decomposition tree As soon as the process has been completed the extraction module queries the scene database in order to find which are the relations and properties that were declared by the designer at the beginning The extraction module then traverses the decomposition tree of the declarative layer in order to find out the respective relations and properties and mark them as designer requirement The rule set consists of these relations and properties 3 5 4 The propagation policy The control module applies a specific propagation policy as soon as a modification occurs Figure 3 19 presents the propagation policy The object under modification and all related objects constitute a set That set will be modified by the system The control module calculates their new positions along with their new dimensions Thus RS MultiCAD has already updated the geometric layer of the stratified representation only for the objects that belong to that set As the geometric layer of the stratified representation has been updated RS MultiCAD must update the declarative layer respectively The process starts from the object under modification where the control module finds out the relations and the properties which have been marked as designer requirements and belong to the collection classes These 86 Chapter 3 relations and properties are applied on the new respective geometric node of
167. the control module activates the explanation module SCALE_RESIZE object Begin If respect_rule_set Then find all related objects End If calculate bounding box with all related objects calculate bounding box with new positions dimensions of all related objects If bounding box in site Then If space available Then update all related objects with new positions dimensions update all descendants of all related objects with new positions dimensions update all ancestors of all related objects with new positions dimensions If respect_rule_set Then check rule_set for all related objects check rule_set for all descendants of all related objects check rule_set for all ancestors of all related objects If OK Then ScaleCode success Return Else backtrack all ancestors to old positions dimensions backtrack all descendants to old positions dimensions backtrack all related objects to old positions dimensions call explanation_module ScaleCode rule_set_ violation Return End If Else ScaleCode success End If Else ScaleCode position_not_available Return End If Else ScaleCode out_of_site Return End If Sa J Algorithm 3 5 Scale and resize operation 90 Chapter 3 3 5 5 3 Insert operation The insert operation allows the designer to add a new object to the scene The new object creation may correspond to a leaf node or an abstract node on the declarative layer of the stratified represe
168. the course of generation e The scene understanding phase The scene understanding phase completes the declarative conception cycle where the scenes solutions are visualised to the designer through a traditional geometric modeller Certain modellers incorporate special mechanisms form scene understanding such as good point of sight static or dynamic or information about what is presented Figure 2 5 presents the declarative conception cycle Scene Description A Phase Scene Understanding Generation Phase Phase Figure 2 5 The declarative conception cycle A declarative modeller permits the designer to describe the desirable scene with specifying the properties of the components that constitute the scene The designer rather than describing the desirable scene he describes the components of the scene Therefore a total property describes the whole of all the components of the scene whereas a local property describes a subset of these components A declarative modeller must incorporate three types of tools 32 Chapter 2 e Description tools are tools that aid the designer to describe the components of the scene with the assistance of a generic or specific vocabulary which reflects the various properties that these components have The modes of interaction are varied natural language graphical user interface et cetera e Generation tools are tools that accept the declarative description of a
169. the object under modification and if all these are valid then the same process continues with the related objects their descendants and accentors This match operation is necessary in order RS MultiCAD to examine if all designer requirements are still valid Designer Match Modification Designer Extraction Requirements Stratified New Stratified x Representation Geometric Representation State ee Nr Backtrack Figure 3 19 The IDEF3 diagram of the propagation policy Otherwise the relations and properties which have been marked as designer requirements are not valid and they are sent to the explanation module The process does not end and continues in order to find out all invalid relations and properties examining the related objects their descendants and ancestors The explanation module is activated informing the designer about the invalid relations and properties Whenever a modification occurs without taking into consideration the rule set the control module through the propagation policy updates both layers of the object under modification its descendants and ancestors without applying the match operation 3 5 5 Scene modifications 3 5 5 1 Move operation A selected scene can be modified by the designer in various ways The move operation offers the designer the ability to alter the position of a selected object and can b
170. ties of the object flat_7 The generalization factor equals to 3 which means that the pure geometric properties of the objects of the third level of detail must be added to the resultant declarative description It must be pointed out that only the objects of the third level of detail with descendants provide their pure geometric properties to the resultant declarative description As a result only the object flat_7 provides its position and dimensions of its bounding box The object living room 5 play room_6 roof 13 roof 14 roof_15 garage 11 storage 12 and Experimental Results 119 roof_16 belong to the third level of detail but since they do not have any descendants they do not provide their pure geometric properties to the resultant declarative description 1000000 100000 10000 No Solutions 2 S 5 Generalization Factor Figure 4 27 Experimental results of automated reduction of the solution space When the generalization factor equals to 4 then all objects of the decomposition tree provide their pure geometric properties to the resultant declarative description As a result this declarative description produces only one geometric solution in the next iteration of MultiCAD indeed The experimental results of all possible iterations of the specific example are illustrated in Figure 4 27 where the z axis of the chart is in logarithmic sc
171. tion of the geometric model In the first case study an internal MultiCAD geometric model is used in order to demonstrate that the Extended Declarative Conception Cycle of MultiCAD operates properly In the second case study an external geometric model obtained from another geometric modeler is used in order to show that RS MultiCAD can operate as a link with other commercial CAD systems The second reason is based on the presentation of representative samples of reality Both case studies incorporate elements which are indicated in real situations In the first case study a block of buildings is evolved while in the second case study a layout of rooms is the objective of the experiment The robustness of the system along with the flexibility are good reasons against the complexity of the case studies Every time the estimation of the results is based on the comparison with the correctness of the result as far as the scene modifications are concerned since the result is qualitative in contrast with the estimation of the results of solution space reduction where the result is quantitative 4 1 RS MultiCAD environment RS MultiCAD environment includes panels menus a display and a toolbar The declarative panel presents information about the decomposition tree of the declarative model and the spatial reflective relations properties of the current selected object The current geometric model is visualized on the graphical display The pu
172. tions sont conformes ou non aux conditions initiales du b timent Le syst me aboutit sur un mod le d claratif qui incarne les modifications du concepteur Cette nouvelle description d clarative est fournie la phase d clarative de description MultiCAD et une nouvelle it ration d bute Une d monstration d une s rie de r sultats exp rimentaux fournit la certitude qu un tel syst me est r alisable et efficace Afin d accomplir le but principal les objectifs suivants doivent tre pris en consid ration e Surmonter les probl mes de l int gration du modeleur g om trique et d claratif dans le cycle conceptuel d claratif Une description de sc ne d clarative produit un ensemble de mod les g om triques alternatifs qui r pondent aux exigences du concepteur D autre part un mod le g om trique peut correspondre plus d une description de sc ne d clarative Ceci se produit parce que le mod le g om trique sp cifique appartient l intersection de plusieurs ensembles de mod les g om triques espaces de solutions qui ont t produits partir de mod les d claratifs diff rents Par cons quent les diff rentes descriptions de sc ne d claratives peuvent mener la m me repr sentation g om trique et aussi une repr sentation g om trique sp cifique pourrait mener plusieurs descriptions de sc ne d claratives e Surmonter les probl mes de saisie d information g om trique et non g om trique
173. tiques g om triques Le cycle conceptuel de la mod lisation d clarative s largi avec l introduction de la phase de la reconstruction ayant comme objectif ultime l accomplissement et la fermeture de la boucle du cycle conceptuel d claratif afin de reconstruire le mod le abstrait de d part La fermeture du cycle conceptuel d claratif rend le fonctionnement du syst me r ellement it ratif assist par ordinateur et elle offre au concepteur la possibilit de raffiner plus efficacement les solutions g om triques produites Le but de la phase de reconstruction est d une part de comprendre s mantiquement la sc ne et d autre part de permettre au concepteur de r aliser des modifications sur la sc ne choisie Pendant la phase de reconstruction un ensemble de r gles et un ensemble d objets sont tablis et mis jour refl tant les exigences de concepteur Les deux ensembles sont dynamiques puisque pendant la phase de reconstruction ils sont toujours susceptibles de modification Afin de comprendre la sc ne s mantiquement le syst me RS MultiCAD utilise une repr sentation stratifi e Sagerer et al 97 Une telle repr sentation capture l information g om trique et d clarative de la sc ne choisie dans la m me repr sentation La repr sentation stratifi e est un mod le de niveau interm diaire qui incarne les deux niveaux de l abstraction en termes de deux couches distinctes reli es ensemble La repr sentation strati
174. to the intermediate model and finally into the respective declarative model The construction mechanism is responsible for receiving a MultiCAD geometric model and converting into the stratified representation The extraction mechanism operates on the stratified representation in order to extract all appropriate relations and properties from the geometry of the objects that constitute the scene Besides RS MultiCAD incorporates an appropriate mechanism which permits the designer to perform modifications on the scene Every designer modification affects the stratified representation The system applies a specific propagation policy in order to properly handle the stratified representation and activates the extraction mechanism perspective to update the intermediate model Finally the intermediate model in converted into the resultant declarative description Figure 3 7 presents the inner operation cycle of RS MultiCAD Thesis Proposal and Implementation 65 Extraction Designer Modifications Construction Stratified Geometric gt Declarative Model no Model Return Declarative Model Propagation Policy Figure 3 7 The inner operation cycle of RS MultiCAD 3 4 1 Data and knowledge storage A brief description of the MultiCAD database is given in Maoulis et al 00 The RS MultiCAD system in order to store a declarative description follows the gui
175. torage_12 is occupied by the object roof_16 but since the two objects are spatially related with a relation according to the rule set the modification is valid Changing the height of the object storage_12 causes a move of the object roof_16 to a new position while the object garage_11 remains at the same position The result is illustrated in Figure 4 13 In case the designer resizes the object storage_12 to a new height equals to 4 without taking into account the rule set the modification is canceled since the position is occupied by another object As already pointed out the modification of the object storage 12 height is applied if and only if the object roof_16 moves to a new position setting the old position available to object storage 12 As soon as the object roof 16 remains at the same position since the rule set is not taken into account the modification is canceled because the position is not available The result is illustrated in Figure 4 14 ege eoe em wiwiG Pipini ation 9 5645 12 9935 0 0000 Figure 4 14 Position not available In case the designer scales the object aux building by 10 the modification is applied The descendants of the object aux building are updated respectively The Experimental Results 109 dimensions rate of the objects remains the same as before the modifications for all concerned objects The result is illustrated in
176. tratifi e et ensuite le module de contr le v rifie et met jour la couche g om trique de la repr sentation stratifi e si aucune relation propri t qui appartient l ensemble de r gles n est viol e Par ailleurs le concepteur effectue les modifications g om triques qui affectent premi rement la couche g om trique de la repr sentation stratifi e et alors le module de contr le v rifie et met jour la couche d clarative de la repr sentation stratifi e si aucune relation propri t qui appartient l ensemble de r gles n est viol e En outre le concepteur a la capacit d ignorer l ensemble de 146 Chapitre 5 r gles et r alise une modification qui m ne au module de contr le pour r arranger la repr sentation stratifi e Le module d explication est responsable pour l approvisionnement d informations valables au sujet du raisonnement du module de contr le dans les cas o une modification du concepteur sur la sc ne violerait l ensemble de r gles Finalement le syst me RS MultiCAD incorpore un interface utilisateur graphique avec une dition en trois dimensions afin de visualiser les mod les g om triques et recevoir de mani re graphique les demandes du concepteur Le syst me RS MultiCAD re oit le mod le g om trique qui a t produit par MultiCAD et aboutit sur une nouvelle description de sc ne d clarative Le module de contr le du syst me RS MultiCAD produit la description d
177. ts and objects without well defined geometry by their nature cannot be represented and even more a complex object may require hard work to be represented Furthermore geometric modelling suffers from poverty on scene construction which obliges the designer to know with precision all objects that constitute the scene in advance A classic geometric model cannot hold information on the non geometric aspects of the objects This may include physical properties such as colour density cost and other properties geometric model misses a level of abstraction which means that the model represents a specific object and not all or few similar objects The geometric model is defined in terms of a precise geometry The designer has to convert his her mental idea into specifications in an imperative way in terms of co ordinates and dimensions of the various objects When the number of different objects is large that turns to be impossible task The designer must be able to describe an image in a more abstract way by stating the relations and the properties of the objects without worrying about the geometry of the objects 2 2 Declarative modelling Declarative modelling is an approach Lucas et al 90 that can deal with the insufficiency of CAD applications Declarative modelling allows the designer to use imprecise information in a scene description The declarative modelling paradigm introduces property based modelling techniques by providing th
178. ts building 2 building_3 and building_4 29 66 become aux building long_building and high_building respectively 4 2 1 2 Move In case the designer moves the object long building to a new position that causes a move of the children of the long building As soon as the new position of the object long building is available and included in the site the new position becomes current position of the object The object long building consists of the object roof 15 and flat 7 which decomposes further to kitchen 8 bathroom 9 and bedroom 10 The modification is propagated to all descendants in order to update their current position accordingly The result is illustrated in Figure 4 3 F e Sene Change Return Optens eame veo qw ww o ene 15 Long o z Is We Wise re Lex emn Vis Tha i e 18 1999 18 6849 0 0000 Relist ON GeoProperties OFF Figure 4 3 Move long_building to new position Experimental Results 101 In case the designer moves the object kitchen_8 to a new position that causes a move of the brothers of the kitchen_8 The object bathroom_9 is adjacent west to the object kitchen_8 and adjacent east to the object bedroom_10 according to the rule set so the objects that are going to move are the bathroom_9 and bedroom_10 as well The new positions are calculated and as they are available and incl
179. ture modelling is nothing more than advanced geometric modelling only offering parametric and constraint based modelling facilities in addition to the normal geometric modelling facilities Almost all current feature modelling systems are parametric history based systems using a boundary representation as main geometric representation History based modelling systems are procedural systems that keep track of information about each modelling operation performed such as the type of feature created its parameter values and its positioning The sequence of modelling operations creates the model history completely determines the 42 Chapter 2 resulting boundary representation The creation of a feature produces the shape imprint characteristic of its feature type Feature instances can be modified by specifying new values for their parameters or be deleted from the model This is achieved by modifying or deleting the respective feature creation operation in the model history The new feature model is evaluated by sequentially re executing the operations in the model history In figure 2 11 a boundary model is illustrated which consists of a base block a blind hole and a protrusion The example is adopted from Bidarra 99 Figure 2 11 A boundary model According to Bidarra 99 history based systems suffer from the strong dependency on the chronological order of the feature creation the limitations of constraint solving and the
180. type roof with position at 0 0 3 and length width height equal to 11 10 2 respectively The parent of the new object is the object site The system examines whether the position is available and included in the site and if so the system creates the new object and updates accordingly the declarative panel along with the graphical display The result along with the output of the previous step is shown in the Figure 4 35 4 3 1 4 Change the geometric characteristics In case the designer changes the extra geometric characteristics of the object roof 11 it causes changes inside the bounding box of the object Changing the geometric characteristics of the Base Weights and B Splines with new values the geometry of the object roof 11 alters The position and the dimensions of the bounding box remain the same as before the modification The result is illustrated in Figure 4 36 M RS MultiCAD X Fle Scone Change Return Options eigiwieieis iss elvis elw S P pimiis Lowm Than house 10 Adjacert vm housm 10 Leng Than ido 4 5410 13 8199 0 0000 Relison ON GeoPropertion OFF Figure 4 36 Change extra geometric characteristics 4 3 1 5 Delete In case the designer deletes a leaf object such as the object roof_11 the object disappears and the system updates all panels in order to reflect the current status of the scene The result is illustrated in Figure 4 37 Experimental Re
181. uded in the site the new positions become current positions of the objects The move of the object kitchen_8 is propagated to brothers because the designer wants to keep the relations that are relative to the specific object but also is propagated to ancestors of the kitchen_8 so the positions of the object flat 7 and long building are updated The object roof 15 remains at the same position since the spatial relation roof 15 is adjacent over to flat_7 is still valid The result is illustrated in Figure 4 4 M RS MultiCAD BC F e Scene Change Return Optens eigo e 9a ww 2121071 AD Figure 4 4 Move kitchen 8 to new position In case the designer moves the object flat 7 to a new position that causes a possible move of the brothers and children of the flat 7 As soon as the new position of the object flat 7 is available and included in the site the new position becomes current position of the object The system propagates the modification to object roof 15 and updates its new position Besides the modification is propagated to ancestors and descendants of the object 102 Chapter 4 flat 7 In other words the system updates the object long building kitchen_8 bathroom_9 and bedroom_10 with their new positions The result is illustrated in Figure 4 5 eaim eei ww eee lo root 13 Xi E runs toot iz
182. ui donne l utilisateur la capacit de d crire une sc ne par d composition descendante de haut en bas diff rents niveaux de d tail L architecture du syst me MultiCAD met en application la mod lisation d clarative par d composition hi rarchique elle accepte une description d clarative elle produit un ensemble de solutions g om triques qui rencontrent la description et elle visualise les solutions par un modeleur g om trique Le but de ce travail est d tablir le processus de r tro ing nierie par le syst me RS MultiCAD qui est un syst me bas sur la connaissance afin de coupler un modeleur d claratif avec un modeleur g om trique classique Le cycle de conception d claratif de la mod lisation d clarative est prolong afin d inclure le processus de r tro conception en introduisant la phase de reconstruction et le processus it ratif de conception qui est support e par ordinateur Pendant la phase de reconstruction le syst me RS MultiCAD re oit une solution g om trique choisie qui est s mantiquement comprise il permet au concepteur d effectuer des modifications g om triques et topologiques sur la sc ne et d bouche sur une description d clarative qui incarne les modifications du concepteur Cette description d clarative r sultante m ne des solutions plus prometteuses et r duit l espace initial de solutions Mots cl s Mod lisation d clarative R tro conception Systems bas sur la connaissan
183. une description d clarative partir d un mod le g om trique d une solution g n r ou s lectionn L exploitation et la gestion de la connaissance qui est ainsi fournie contribue sensiblement rendre le syst me de CAO d claratif beaucoup plus souple pour le concepteur qui dor navant voit ses besoins d intervention dans le processus de retro conception se r duire D ailleurs le concepteur peut guider le syst me avec une plus grande souplesse partir du moment o toutes les informations n cessaires sont disponibles afin que le syst me produise un ensemble de solutions g om triques qui seront plus respectueuses des exigences N anmoins la compr hension et la gestion s mantiques des sc nes ouvrent une nouvelle voie mais n cessitent aussi des am liorations sensibles pour tre plus efficace Pour l instant le concepteur choisit une solution g om trique qui peut tre dit Une recherche ult rieure du syst me courant est la possibilit pour le concepteur de choisir plus d une solution g om trique Le multi choix des mod les g om triques m ne gagner certaines caract ristiques d un mod le et d autres caract ristiques d un autre mod le g om trique L unification de ces caract ristiques dans la m me description d clarative de sc ne peut mener un ensemble de mod les g om triques alternatifs dans la prochaine it ration qui exprime les exigences du concepteur plus facilement et plus rapi
184. urn dialog box which contains two radio buttons One radio button is used for the reduction of the solution space by the manual way and the other is used for the reduction of the solution space by the automated way When the radio button for the automated way is checked a track bar slider is appeared and is used for visually adjusting a numeric setting The track bar is used in order the designer to specify the generalization factor of the resultant declarative description 98 Chapter 4 4 1 1 Select mode An object can be selected either by clicking on the declarative panel or on the graphical display On the declarative panel the decomposition tree offers to the designer the ability to select a leaf node or an abstract node as well When the designer selects a node all panels present the respective information of the node On the graphical display the selection of an object updates the panels with all relevant information of the object An additional operation the multi selection is supported The multi selection permits the designer to select an abstract object after selecting all its descendants from the graphical display In Figure 4 1 the selection of building 5 object can be done by selecting the object living room 1 from the graphical display holding down the CTRL button and continue selecting the kitchen_2 bedroom 3 and bathroom_4 object from the graphical display Besides if the designer continues sel
185. ven detail level even if the description includes additional levels of detail e The generation process insures the inheritance of properties by means that the bounding box of a scene includes all bounding boxes of its sub scenes MultiFormes is a declarative modelling prototype system and implements the hierarchical decomposition which has been developed at the laboratory XLIM of the University of Limoges MultiFormes models complex scenes by hierarchical decomposition Plemenos 95 Bonnefoi 99 Ruchaud 01 where a scene is decomposed into sub scenes which are recursively described by the designer up to a certain level of detail MultiFormes Plemenos 95 deals with complex scenes and the hierarchical decomposition is implemented by dividing these scenes into a number of sub scenes The hierarchical decomposition allows the designer to describe a complex scene by top down decomposing into a number of sub scenes and results to decrease the complexity of the whole scene The decomposition of the scene can be recursive permitting the designer to describe the scene by using logical and spatial criteria The designer builds a hierarchical decomposition tree which contains nodes The hierarchical decomposition is implemented by declaring that a specific node is decomposed into a number of descendants The description of the descendants is easier concerning the complexity of the ancestor Apart from the logical and spatial decomposition of the sc
186. w is a CAD system built using ActiveX technology It can be integrated with any developing environment that supports ActiveX components and gives the freedom of choosing a platform that corresponds with the developer needs Provides an object oriented perspective of a CAD document and supports the most widely used file formats The supported file formats are the followings e All Drawing vdf vdi vdp xml emf wmf VectorDraw is trademark of VectorDraw Corporation 176 Appendix C e VectorDraw Files vdf e VectorDraw Compressed files vdi e VectorDraw Project Files vdp e XML Document xml e EMF Files emf e WMF files wmf e DXF files dxf vdrawDXF dll required e All images bmp gif jpg tif tga png VectorDraw component fulfils the above requirements and is used as a traditional geometric modeller which is integrated with RS MultiCAD system Below further VectorDraw characteristics are presented The object model of VectorDraw component consists of various objects which the developer has the ability to manage in order to create a CAD application without be concerned about graphics library implementation details The object model is presented in Figure C 1 The major object is vdDocument which maps all the information of a CAD drawing vdDocument has methods to open save and export a document that saves the developer from parsing complex file formats vdDocument holds collections of blocks la
187. xisting object When the designer selects the Move menu command the Move dialog box appears where the designer has to specify the new position of a selected object When the designer selects the Scale Resize menu command the Scale Resize dialog box appears which contains a tab control The tab control is used to appear a dialog box for the Scale command and another dialog box for the Resize command On the Scale dialog box the designer has to specify the percentage of scaling of a selected object On the Resize dialog box the designer has to specify the new dimensions of the bounding box of the selected object When the designer selects the Insert menu command the Insert dialog box appears A tab control is used to appear a dialog box for the insertion of a leaf node and another dialog box for inserting an abstract node On the Leaf Node dialog box the designer has to specify the object type the node that will become parent the position on the scene and the dimensions of the bounding box of the inserted object On the Abstract Node dialog box the designer has to specify the object type the node that will become parent along with the nodes that become children of the inserted object When the designer selects the Delete menu command a confirmation dialog box appears in order the designer to verify the deletion of a selected object The Return menu activates the Ret
188. yers images etc The most important collection is the vdEntities collection which stores the drawing elements of the document The developer can easily add new objects to the document by simple add them to vdEntities collection For example the code to add a line is VDraw ActiveDocument Entities AddLine StartPoint EndPoint where StartPoint and EndPoint are double arrays with the corresponding coordinates The Traditional Geometric Modeller 177 vdactions vdxyz 1 vdxPropert vdEntities vdBlocks vdDimstyles vdHatchPatterns vdImages vdLayers vdLayouts vdLights vdLineTypes vdPrint vdSelections vdTextstyles vdCommand vdColor vdPalette vdDataObject vdPalette vdmatrix x a m o a m vd Utilit Figure C 1 The object model of VectorDraw The vdFigure is the base class for all drawing elements and has the common properties and methods Every drawing entity such as line circle etc inherits from vdFigure and extends it with extra methods and properties Titre tude et r alisation d un syst me de r tro conception bas sur la connaissance pour la mod lisation d clarative de sc nes R sum La mod lisation d clarative permet au concepteur de d crire sans devoir d finir les propri t s g om triques une sc ne en pr cisant ses propri t s qui peuvent tre impr cises et incompl tes La mod lisation d clarative par d composition hi rarchique est une approche sp ciale q

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