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Physical Properties User Guide and Menu Reference

1. B 2 Physical Properties User Guide and Menu Reference Improving Mass Properties and Volume Calculations The Projection and Rotation Method CENTROID X 20V 4S 2508 2 0 FIRST MOMENTS Myz 8 3775806 Mxz 8 3775806 Mxy 8 3775806 MOMENTS OF NERTIA Ixx 35 1858367 Tyy 35 1858367 Izz 35 1858367 PRODUCTS OF NERTIA Ixy 16 7551612 Ixz 16 7551612 Iyz 16 7551612 n CALCULATE MPROPERTIES PROJECT HIBND 4 TAG M2 PLEASE DIGITIZE TWO POINTS TO DEFINE PROJECTION AXIS MODEL loc X0Y0Z0 X0Y0Z1 PLEASE ENTER SOLID BOUNDARY 1 dddd PLEASE ENTER SOLID BOUNDARY 2 VOLUME 64 0 MASS 64 0 CENTROID X 2 0Y 2 0Z 2 0 FIRST MOMENTS Myz 128 0 Mxz 128 0 Mxy 128 0 MOMENTS OF NERTIA Ixx 682 6666869 Iyy 682 6666869 zz 682 6666869 PRODUCTS OF NERTIA Ixy 256 0 Ixz 256 0 Iyz 256 0 n MERGE MPOINT SUBTRACT TAG M3 MODEL ent TAG M2 MODEL ent TAG M1 n LIST MPOINT MODEL ent TAG M3 VALUES ARE GIVEN WITH RESPECT TO MODEL SPACE COORDINATES Tag M3 VOLUME 59 8112106 MASS 59 8112106 CENTROID X FD ONS 2020 FIRST MOMENTS Myz 119 622421
2. 1 000000 Kg mm3 MXZ ITALY Iks 255999999 999938 mm3 255999999 999938 Kg 11999999 999995 mm2 1809 063665 Y 1385 514831 3 54692e 11 3e 15 IZZ PRODUCTS OF INERTIA IXY 2 32e 14 IXZ 2 055e 13 Z IYZ 44 375 mm MXY 1 136000e 10 Kg mm 3 5e 15 Kg mm2 1 57e 13Kg mm2 2 Save Data to Filename option specified scientific format 1996 DATE Fri Jul 26 10 10 10 PART NAME ULEN mm UWGT Kg DESCR IRON_16500 HARD ITALY TAG MP1 ASSMIP 4 ASSTAG SOL1 ASSLAY 10 CPL USER CPLOX 2500000E 03 CPLOY 500000E 03 CPLOZ 000000E 03 CPLXX 0000000E 00 CPLXY 0000000E 00 CPLXZ 000000E 01 CPLYX 000000 CPLYY 1 000000 CPLYZ 000000 CPLZX 1 000000 CPLZY 000000 CPLZZ 000000 DENS 1000000E 01 VOL 2560000E 09 SAREA 1200000E 08 MASS 2560000E 09 CMX 1809064E 04 CMY 1385515E 04 CMZ 4437500E 02 FMX 4631203E 12 FMY 3546918E 12 FMZ 1136000E 11 IXX 2172464E 16 users mvalenti parts testpart Physical Properties User Guide and Menu Reference 5 5 Working with Mass Points Reporting Mass Point Data IYY 1297764E 16 IZZ 3468752E 16 IXY 2315693E 15 IXZ 2055096E 14 IYZ 1573945H 14 3 Save Data to Filename option spec
3. 4 16 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating Mass Properties Using Cross Sections Calculating Mass Properties Using Cross Sections The following example calculates the mass properties of a pyramid section containing an interior cylindrical hole using the cross sections method In the example the object has been sectioned by planes perpendicular to the z axis at a distance of one inch between each cross section Please note Select an empty layer by selecting Layer from the Status area of the top bar and SELECT from the Layer menu when using the cross sections method with layer echoing otherwise undesired graphics may remain on the screen 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Calculate Mass Properties icon from the menu 3 When the property sheet appears select the Cross Sections Method icon 4 Select the options you want and enter the necessary information Physical Properties User Guide and Menu Reference 4 17 Calculating Mass Properties Calculating Mass Properties Using Cross Sections In the example the chosen options are e Subtract hole s e Calculate surface area e Calculate 6 cross sections e Starting layer is 4 e Increment the layer by 2 Incremen 1 0000000000 _ Unit Lb Z ing Apply 5 Select Apply The following menu appears on the property sheet More bounda
4. a Report Units Density Unit Lb ind Apply 3 When the property sheet appears select the Save data to file option and enter a name for the file Select any other desired options Select Apply In the graphics window select the three mass points ya oa TO A Select Done from the Utilities menu You can view the information in the file created at the operating system level The file is stored under the _bcd subdirectory of the active part See Highlighting Mass Point Associations to learn about highlighting mass point associations See Updating Associative Mass Point to learn about updating mass point associations Physical Properties User Guide and Menu Reference 5 21 Working with Mass Points Changing Mass Point Data Changing Mass Point Data You can change the mass properties data contained in a mass point The new data are checked for consistency before the change is made When you specify second moment data for a mass point that did not previously contain second moments specify all of the appropriate moments Ixx Ixy and Iyy for 2 D mass points and Ixx Ixy Ixz Iyy lyz and Izz for 3 D mass points Because changing the first moments also changes the location of the centroid use the Translate Entity icon for this purpose The second moments will be changed accordingly Selecting the Mass Point icon from the Physical Properties menu displays the Mass Points property shee
5. Please note To store physical properties data in a text file use the List Mass Point property sheet with the Save Data to File option enabled See Chapter 5 Reporting Mass Point Data to learn more about this feature In addition to creating mass points to store the results of area volume and mass properties calculations you can also create a mass point to store other aspects of an object These include e Density e Part Unit e Part Identifier full name of active CADDS part e Date of calculation e MIP TAG and Layer of solid Tsurf used in calculation e Description as defined by the DESCR property value in CADDS often used for material identifier These other aspects can be listed using the List Mass Point property sheet by enabling the Generate Detailed Reports option See Chapter 5 Reporting Mass Point Data to learn more about this feature Physical Properties User Guide and Menu Reference 1 3 Getting Started Overview of Physical Properties Functions During the calculation of mass properties you can create mass points on multiple solids CADDS assigns mass properties of each solid you select to the respective mass point CADDS allows you to select a maximum of 600 objects at a time Mass points can be associative or nonassociative Mass points can optionally be merged to created composite mass points to determine weight center of gravity and other properties of multiple objects Please no
6. This option is only available for a solid or Tsurf See Chapter 4 Calculating Mass Properties Using a Solid and Associativity for an example The following options are available Option Density n Tag Unit Description Specifies the density of the object default is 1 0000000000 Assigns a tag to the mass point Tag names are limited to six alphanumeric A Z 0 9 characters Specifies the weight and length units used for the density measurement You can specify either Centimeter Gram Second Inch LB mass second Meter Kilogram Second or specify other combinations of metric and English weight and length units If no unit is specified no unit is used 3 When finished choosing the options you want select Apply A menu appears on the property sheet with options related to those chosen on the property sheet 4 In response to prompts appearing at the command line enter the information as directed using the menu options 5 When finished select Done from the property sheet menu CADDS performs the calculations and reports the results In the Parametric environment the description appears automatically in the Report Window but does not appear in the text window In the Explicit environment the description of the component or components is by default displayed only in the text window To view the description of the object or objects in the Report Window in Explicit environment set the environment va
7. You can delete associated mass points and or the solid Tsurf to which a mass point is associated The selected entities are deleted and the remaining relationships are updated If all associations to the mass point are deleted the isolated mass point is also deleted The following conditions exist e When you delete a solid Tsurf that contains an associated mass point the associated mass point is deleted automatically e If the associated mass point is also a source mass point of a merged mass point it is removed from the list of source mass points that comprise the merged mass point This is also true if you delete the source mass point itself e When you delete a merged mass point the association between the merged mass point and it s source mass points is automatically deleted The source mass points are left intact e If the merged mass point deleted is also a source mass point of another merged mass point it is removed from the list of source mass points that comprise the next level merged mass point 5 28 Physical Properties User Guide and Menu Reference Chapter 6 Calculating Center of Gravity This chapter provides information about calculating center of gravity e Overview of Calculating Center of Gravity e Calculating Center of Gravity Physical Properties User Guide and Menu Reference 6 1 Calculating Center of Gravity Overview of Calculating Center of Gravity Overview of Calculating Center
8. Cone generated by a Sphere generated by a triangle closed half circle Torus generated by acircle Physical properties are calculated based on the closed boundary from which the 3 D object is generated 1 6 Physical Properties User Guide and Menu Reference Getting Started Overview of Physical Properties Functions Requirements for an Implied Tabulated Cylinder To calculate physical properties for an implied tabulated cylinder 1 All boundary curves must lie in the same plane 2 The axis of projection must not lie in the same plane as the boundary curves 3 The number of closed boundaries solid and holes is not limited but the number of entities in each boundary must be fewer than 300 Please note Because all physical properties calculations are based on the defining curves it is not necessary to create any surfaces or solids Please note An example Se oa Cylinder generated by a Pipe generated by tyro Box generated ky circle concentric circles a Square Physical properties are calculated based on the closed boundary from which the 3 D object is generated Object Defined by Cross Sections To calculate the properties of an object that cannot be defined by the rotation or projection of a bounded region represent the object as a series of cross sections In this method physical properties are calculated for each cross section and then summed to approximate the physical properties of the object Each c
9. area is subtracted from the total positive area to calculate the resulting area Tag Assigns a tag to the mass point Tag names are limited to six alphanumeric A Z 0 9 characters 3 When finished choosing the options you want select Apply The menu appears on the property sheet with options related to those chosen on the property sheet Physical Properties User Guide and Menu Reference 2 3 Calculating Areas General Area Calculation Procedures 4 In response to prompts appearing in the command line enter the information as directed using the menu options To ensure that the calculated results are correct make sure that all boundaries selected lie on a single plane and that no boundary intersects itself 5 When finished select Done from the property sheet menu The system performs the calculations and reports the results in the text window 2 4 Physical Properties User Guide and Menu Reference Calculating Areas Calculating Combined Areas Calculating Combined Areas The following example calculates the combined area of a square and a circle 1 Select the Physical Properties icon from the Model Taskset on the side bar 2 Select the Calculate Area icon from the menu 3 When the property sheet appears select the Calculate Bounded Area icon Calculate Area Mass point Hole Apply 4 Select Apply The following menu appears on the property sheet 5 In the graphics window select the
10. software products see the PTC Customer Service Guide It includes instructions for using the World Wide Web or fax transmissions for customer support Physical Properties User Guide and Menu Reference Preface Documentation Comments PTC welcomes your suggestions and comments You can send feedback electronically to doc webhelp ptc com Physical Properties User Guide and Menu Reference xi Chapter Getting Started This chapter describes the Physical Properties software and explains how to use it e Overview of Physical Properties Functions e Using Physical Properties e Extracting Parametric Mass Properties Data Physical Properties User Guide and Menu Reference 1 1 Getting Started Overview of Physical Properties Functions Overview of Physical Properties Functions You can calculate various physical properties of the CADDS models Explicit Environment Within the Explicit environment CADDS 5 Physical Properties software allows you to calculate the following properties of bounded planar regions and volumes enclosed by surfaces e Volume e Area e Mass e First moments e Center of mass e Moments and products of inertia with respect to the model space x y and Z axis e Moments and products of inertia with respect to an arbitrary coordinate system e Polar moment of inertia about a point e Radius of gyration e Principal axes e External surface area e Center of gravity Numeric Accuracy
11. 1 Options on the List Mass Point Property Sheet Option Description Relative to mass points Indicates that the mass property values are to be listed with respect to the coordinate system of the named Cplane You can use this option in conjunction with the Polar option default implying a translation of the Cplane origin to the centroid You select the Cplane from the list of existing Cplane names that appear Command output states the named Cplane and it s transformation data relative to the Top Cplane Save Data in Decimal Saves the data to the external file using fixed format with 15 figures Format and 6 decimal places If 15 figures is not sufficient the output is automatically switched to scientific notation with 7 significant digits Generate Detailed Reports Lists the following additional information density part unit part identifier full name of active CADDS part date of calculation MIP tag and layer of solid tsurface used in the calculation and CPL transformation data Report Units Specifies the weight and length units used in the report You can specify either Centimeter Gram Second Inch LB mass second Meter Kilogram Second or specify other combinations of metric and English weight and length units If no unit is specified no unit is used in the report Please note Since all values are with respect to model space coordinates Top Cplane use the Relative to mass point Cplane option if the coordinate system in
12. 5 Working with Mass Points This chapter provides instructions for reporting inserting merging and changing mass point data Reporting Mass Point Data Inserting Mass Point Data Merging Mass Point Data Changing Mass Point Data Updating Associative Mass Point Highlighting Mass Point Associations Breaking Mass Point Associativity Deleting Mass Points and Associated Entities Physical Properties User Guide and Menu Reference 5 1 Working with Mass Points Reporting Mass Point Data Reporting Mass Point Data You can report the data contained in a mass point including Volume or area Mass Surface area Centroid First moments Moments of inertia Products of inertia Please note Density is not currently stored in mass point data base but can be computed as Mass Volume Polar moment of inertia Radius of gyration Principal axes axes of symmetry Principal moments of inertia Additionally you can report the following information using the Generate Detailed Reports property sheet option Part unit Part identifier full name of CADDS part Date of calculation MIP tag and layer of Solid Tsurf used in computation if mass point associativity is used CPL transformation data with respect to Top Cplane of the user entered CPL CPLANE modifier in the following format CPL ORIGIN IN MODEL SPACE X Y Z Unitized Vectors for X Y Z axes Besides reporting the data in the text window you can optio
13. 5 15 options 5 14 List Mass Point property sheet 5 3 merging data 5 17 example 5 19 options 5 19 reporting data 1 15 5 2 examples moment of inertia and axis of Physical Properties User Guide and Menu Reference Index 1 Index gyration 5 8 polar moment of inertia 5 4 5 7 principal axes 5 10 options 5 3 procedures 5 2 symbol 1 3 Mass Points property sheet 5 13 change options 5 22 insert options 5 14 merge options 5 18 Mass properties calculations Calculate Physical Properties property sheet 4 3 cross sections method C 1 examples cross sections method 4 17 projection method 4 10 rotation method 4 13 methods for improving results B 1 options 4 3 procedures 4 2 4 3 Mass Properties menu 1 9 Mass table example 6 3 format 6 5 header line 6 5 Messages A 2 O Object types 1 4 defined by cross sections 1 7 implied surface of revolution 1 6 implied tabulated cylinder 1 7 two dimensional 1 5 P Physical properties calculations 4 2 Physical Properties software numeric accuracy factors 1 2 object types supported 1 4 options 1 9 overview 1 2 parametric functions 1 16 preliminary procedures 1 9 Plant Design calculating center of gravity 6 3 Printing documentation from Portable Document Format PDF file 1 x S Structural Modeling System calculating center of gravity 6 3 Structural Steel Modeling calculating center of gravity 6 3 System messages A 2 1 This 5 1 V Volume calculations cr
14. ASSOCIATIVE operation is no longer present in the component V VIEWED IN MASS POINT CANNOT BE MOVED TO LAYER MARK MPOINT VIEWED IN SOLID OR TSURF CANNOT BE MOVED TO LAYER MARK MPOINT VOLUME OF NEW MASS POINT NOT GREATER THAN ZERO INSERT MPOINT W WARNING NO ACCURACY VALUE RETRIEVED FROM MASS POINT MIP SETTING ACCURACY VALUE TO DEFAULT 2 UPDATE MPOINT Y YOU MUST SELECT EITHER PROJ ROT XSECT OR PLANE PLEASE RE ENTER MODIFIERS CALCULATE MPROPERTIES CALCULATE VOLUME A 8 Physical Properties User Guide and Menu Reference Appendix B Improving Mass Properties and Volume Calculations This appendix contains some suggestions for obtaining the greatest possible accuracy from mass properties and volume calculations The two methods for obtaining the greatest possible accuracy from mass properties and volume calculations are The projection and rotation method and The cross section method The projection and rotation methods for calculating mass properties and volume information provide exact answers within the numerical accuracy of the system while the cross sections method involves an approximation described in detail in Appendix C Cross Sections Method Calculations e The Projection and Rotation Method e The Cross S
15. Ag 3 Fle Fee Ilza I ze inpe HSPN Al AVS 4 Fly P2peE 24 Fin Pan MF S234 xy T2xy B IRIRA ADS Eilr ERX 0244 Fin Ea 8 ENE 34 Linz 2x prs H SUP AL ADVE Eir 2220 F 24 lp ERAF 2y dipr T2y2 Here F1 and F2 are the first moments of S1 and S2 I1 and I2 are the second moments of S1 and S2 and X Y and Z are the components of the vector from CM1 to CM2 that is CM2 CH1 Xi Yj Zk Physical Properties User Guide and Menu Reference C 3 Index A Area calculations Calculate Area property sheet 2 3 examples area defined by polygon window 2 9 area with holes 2 7 combining areas 2 5 options 2 3 procedures 2 2 C Calculate Area property sheet 2 3 bounded area options 2 5 2 7 polygon window area options 2 9 Calculate Center of Gravity property sheet 1 14 6 4 weight units 6 6 Calculate Physical Properties property sheet cross sections method options 4 18 projection method options 4 11 rotation method options 4 14 Calculate Volume property sheet cross sections method options 3 14 projection method options 3 8 rotation method options 3 11 D Documentation printing from Portable Document Format PDF file 1 x G Gravity calculating center of 1 14 Inner Hull Design calculating center of gravity 6 3 L List Mass Point property sheet 5 3 M Mass points calculating center of gravity 6 2 changing data 5 22 options 5 22 function 1 3 inserting data 5 13 example
16. Calculating Volume Selecting the Calculate Volume icon displays the following property sheet Calculate Volume point a End depth 1 0000 Apply The options on this property sheet allow you to calculate the volume of an object using the e Projection method e Rotation method e Cross sections method e Create a mass point to store the calculations Directions for calculating volumes are in Chapter 3 Calculating Volumes Physical Properties User Guide and Menu Reference 1 11 Getting Started Using Physical Properties Calculating Mass Properties Selecting the Calculate Mass Properties icon displays the following property sheet Calculate Physical Properties Mass point tart dep Hole E urface area a End depth 1 0000 Density 1 0000000000 Unit Lb zZ ind Apply The options on this property sheet allow you to calculate the mass properties of an object using the e Projection method e Rotation method e Cross sections method e Create a mass point to store the calculations Additionally you can calculate the mass properties of a solid object and an object defined as a volume enclosed by one or more surfaces Directions for calculating mass properties are in Chapter 4 Calculating Mass Properties Physical Properties User Guide and Menu Reference Getting Started Using Physical Properties Working with Mass Points Selecting the Mass Points icon from the Phys
17. Mass Table Format The mass table must have a keyword header line and a row of values for each entity for which you want to calculate center of gravity In addition the mass table can have an optional units line and any number of comment lines Comment lines are identified by an asterisk in the first column of the line The units line specifies the weight units type in the mass table It is written as UNITS wunits This line must be the first uncommented line if it exists Possible units below Abbreviation Unit LB Pounds KG Kilograms LTONS Long tons 2240 pounds STONS Short tons 2000 pounds MTONS Metric tons OZ Ounces GM Grams Header Line Keywords The header line contains the following keywords in any order e IDENTIFIER This is the value of the property used to identify the entity such as STOCKNO for piping e XOFFSET Along with YOFFSET and ZOFFSET these values specify an offset from the origin of the entity to be used as the center of gravity e YOFFSET e ZOFFSET e WEIGHT The weight of the entity e WEIGHT LENGTH The weight per unit length of the entity You can specify either WEIGHT or WEIGHT LENGTH for a given identifier You should specify WEIGHT LENGTH for pipe duct and steel weights If the units line exists the header line must be the second uncommented line If the units line does not exist the header line must be the first uncommented line Values for each entity m
18. Physical Properties User Guide and Menu Reference 5 17 Working with Mass Points Merging Mass Point Data If the association fails for any reason the merged mass point is created without any association relationship and the following message appears Error in associating Mass Points creating a non associated Merged Mass Point Please note Itis currently not possible to create associations to mass points that are not physically resident in the active part Merge Options 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Mass Point icon from the Physical Properties menu to display the Mass Points property sheet When you select the Merge option the following options appear Mass Points Subtract Replace original mass points Associative 5 18 Physical Properties User Guide and Menu Reference Working with Mass Points Merging Mass Point Data You can select one of the following options when merging mass points Table 5 3 Options on the Merge Mass Point Property Sheet Option Description Add Adds the indicated mass points Subtract Subtracts the second and subsequent mass points from the first one You can select the following options with either the Add or Subtract options Table 5 4 Add Subtract Options Option Description Replace original Deletes the original source mass points of the merged mass point Associative Creates an association between th
19. Properties Calculating the Mass Properties of a Rotated Object In the example the chosen options are to calculate the surface area and create a mass point Calculate Physical End angle 360 00 Density 1 0000000000 _ Unit Lb zZ ind 6 In response to the MODEL loc prompt in the command line select two locations to define the rotation axis 7 In response to the following prompt in the command line select the lines in order to identify the boundary 4 14 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating the Mass Properties of a Rotated Object Please Enter Solid Boundary 1 Defines taton as 8 Select Done from the property sheet menu The system calculates the mass properties and center of mass Then it creates a mass point symbol at the calculated centroid position and reports the results in the text window VOLUME 53 4070701 MASS 53 4070701 SURFACE AREA 91 1061782 CENTROID X 0 0000002 Y 1 1617647 Z 0 0 Ixy 0 0000125 Ixz 0 0 Iyz 0 0 FIRST MOMENTS Myz 0 000012 Mxz 62 0464515 Mxy 0 0 MOMENTS OF INERTIA Physical Properties User Guide and Menu Reference 4 15 Calculating Mass Properties Calculating the Mass Properties of a Rotated Object Ixx 201 7425994 Iyy PRODUCTS OF INERTIA Ixy 0 0000125 Ixz 0 0 Tyz 0 0 202 0043945 Izz 201 7425842
20. Select Apply The following menu appears on the property sheet 6 In response to the MODEL loc prompt in the command line select two locations to define the rotation axis 7 In response to the following prompt in the command line select the lines in order to identify the boundary Physical Properties User Guide and Menu Reference 3 11 Calculating Volumes Calculating the Volume of a Rotated Object Please Enter Solid Boundary 1 d2 Defines rotation axis 43 di d4 d dS d 8 Select Done from the property sheet menu The system calculates the volume and center of mass Then it creates a mass point symbol at the calculated centroid position and reports the results in the text window VOLUME 53 4070701 MASS 53 407067 SURFACE AREA 91 1061782 3 12 Physical Properties User Guide and Menu Reference Calculating Volumes Calculating a Volume Using Cross Sections Calculating a Volume Using Cross Sections The following example calculates the volume of a pyramid section containing an interior cylindrical hole using the cross sections method In the example the object has been sectioned by planes perpendicular to the z axis at a distance of one inch between each cross section Please note Select an empty layer by selecting Layer from the Status area of the top bar and SELECT from the Layer menu when using the cross sections method with layer echoing otherwise undesired graphics m
21. The CADDS numeric representation extends to 7 significant digits However the iterations and complex computations used limit the actual precision to approximately five significant digits for direct analytic techniques such as projection and rotation Additionally these numeric precision limitations affect the number of accurate decimal places For example the use of three digit numbers results in answers accurate to two decimal places As the accuracy of a calculation is influenced by numerical and methodological effects we recommend that you test the routine for each class of parts Compare the software answer to known answers and derive an accuracy estimate from the comparisons The comparisons provide reasonable guidelines for the accuracy of the total procedure for each class of measurement 1 2 Physical Properties User Guide and Menu Reference Getting Started Overview of Physical Properties Functions The Mass Point Mass points provide a way to store physical properties data in the Explicit environment Each time you perform a calculation you can create a mass point CADDS uses the standard center of mass symbol to identify the location of the object s centroid center of mass You can change this location with the Move icon Mass point syrmnbol You can also store physical properties data outside the part database in a standard text file allowing you to quickly transfer physical property data to and from mass points
22. To work with Physical Properties within the CADDS 5 Explicit environment activate a part that has entities in it For information on how to use the CADDS interface see the Explicit Solid Modeling User Guide and Menu Reference Physical Properties Options When you select the Physical Properties icon from the Model task set the following menu appears Physical Associative Wess Poiats f Zgncel The icons are labeled from left to right below e Calculate Area e Calculate Volume e Calculate Mass Properties e Mass Points Insert Merge Change e Calculate Center of Gravity e Update Select Associations e Update All Associations e Highlight Associations e Move Highlit Associations to Layer n e Break Association Physical Properties User Guide and Menu Reference 1 9 Getting Started Using Physical Properties Please note Mass points created by calculating mass properties or merging mass points can be associative or non associative Calculating Area Selecting the Calculate Area icon displays the following property sheet The options on this property sheet allow you to e Calculate the area within an enclosed boundary e Calculate the area within a defined polygon window e Create a mass point to store the calculations Directions for calculating areas are in Chapter 2 Calculating Areas Physical Properties User Guide and Menu Reference Getting Started Using Physical Properties
23. axis This axis must lie in the plane of the boundaries All boundaries must be coplanar and cannot be self intersecting 4 4 Physical Properties User Guide and Menu Reference Calculating Mass Properties General Mass Properties Calculation Procedures If you select the rotation method to calculate mass properties the following options are available Option Description Start angle Specifies the minimum extent of the angle of rotation default 0 which is measured from the plane of the boundaries according to the right hand rule End angle Specifies the maximum extent of the angle of rotation default 360 which is measured from the plane of the boundaries according to the right hand rule Using a Series of Cross Sections This option enables you to calculate mass properties using a series of cross sections If you select the cross sections method to calculate mass properties the following options are available Option Description Sections Specifies the number of cross sections defining the object default 2 Start layer Specifies the layer on which the first cross section is identified default layer 1 Increment layer by Specifies the increment in the layer number for successive cross sections default 1 Please note The cross sections method may not accurately calculate mass properties because the variation of the shape of the part between cross sections is not known Therefore
24. entity name 1 00000 Volume 0 614275 in3 Surface Area 4 485941 in2 Mass 9 828397 oz mass Centroid x Y Z 1 077685 0 095642 0 000009 inch Center of Mass x y z 1 077685 0 095642 0 000009 inch 1st Mass Moment x y z 0 055166 0 004896 0 000000 ft lbm Moments of Inertia Moments xXxX Yy 2ZZ 1 375566 12 642074 12 683438 ozm in2 Products xy yz zx 0 859250 0 000035 0 000064 ozm in2 Radii of Gyr x y z 0 374110 1 134143 1 135997 inch Principal Moments of Inertia Moments x y z 1 310411 12 707229 12 683438 ozm in2 Radii of Gyr x y z 0 379169 0 334542 0 346320 inch Principal Axes Normalized Principal Axis 1 0 99714 0 07561 5 3475e 06 Principal Axis 2 0 07561 0 99714 0 001667 Principal Axis 3 0 00012071 0 0016626 1 Physical Properties User Guide and Menu Reference Chapter 2 Calculating Areas This chapter provides instructions for calculating the areas of bounded regions combined regions regions containing holes and unbounded regions defined by polygon windows e General Area Calculation Procedures e Calculating Combined Areas e Calculating an Area with Holes e Calculating an Area Defined by a Polygon Window Physical Properties User Guide and Menu Reference 2 1 Calculating Areas General Area Calculation Procedures General Area Calculation Procedures You can compute the area inside one or more closed boundaries for a two or three dimensional object optionally subtract
25. in the center OFF Round empty ON Diamond filled OFF Diamond empty Toggle key ON Square with a check mark ON Square filled OFF Square empty OFF Square empty viii Physical Properties User Guide and Menu Reference Preface Online User Documentation Online documentation for each book is provided in HTML if the documentation CD ROM is installed You can view the online documentation in the following ways e From an HTML browser e From the Information Access button on the CADDS desktop or the Local Data Manager LDM Please note The LDM is valid only for standalone CADDS You can also view the online documentation directly from the CD ROM without installing it From an HTML Browser 1 Navigate to the directory where the documents are installed For example usr apl cadds data html htmldoc UNIX Drive usr apl cadds data html htmldoc Windows 2 Click mainmenu html A list of available CADDS documentation appears 3 Click the book title you want to view From the Information Access Button on the CADDS Desktop or LDM 1 Start CADDS 2 Choose Information Access the i button in the top left corner of the CADDS desktop or the LDM 3 Choose DOCUMENTATION A list of available CADDS documentation appears 4 Click the book title you want to view From the Documentation CD ROM 1 Mount the documentation CD ROM 2 Point your browser to CDROM_mount_poin
26. point and stored in the new e For geometric mass point the mass properties of the associated explicit or parametric Solid Tsurf are recomputed and stored in the new geometric mass point e For merged mass point a new merge operation between the associated source mass points is performed and the computed mass properties are stored in the new merged mass point e For source mass points if the selected mass point is related to other merged mass points then all the merged associations are also updated As each mass point is updated the following message appears The Mass Point MIP has been updated All association relationships are regenerated 5 24 Physical Properties User Guide and Menu Reference Working with Mass Points Updating Associative Mass Point The following conditions exist e The update function does not check whether the solid Tsurf or source mass point associated to the selected mass point has been changed The mass point update is always performed e The associative mass point is not duplicated when you duplicated an existing solid or Tsurface To create an associative mass point for the new solid Tsurf you must use the Calculate Physical Properties property sheet e The Update function is not performed automatically when an associated solid Tsurf or associated source mass point is changed You must request the function using one of the Update Associative Mass Point icons Physical P
27. specify must be small compared to the curvature of the surface When you do not specify a thickness the thickness is assumed to be infinitesimally thin The default is a thickness of zero When you specify a default thickness of 0 the density is defined as mass per unit of area The more the thickness of the surface the less the accuracy of the results CADDS warns you when the thickness has become too large 4 6 Physical Properties User Guide and Menu Reference Calculating Mass Properties General Mass Properties Calculation Procedures Please note When you use this option apply the property sheet and select the object you are prompted as shown below CALCULATE MPROPERTIES TSURF THICKNESS 2 ASSOCIATIVE lt dig gt Type ok to thicken surface on this side e Accuracy When specifying accuracy start with a small number increment it and perform the calculation again If the two results are similar the accuracy is high Otherwise increment the accuracy and perform the calculation again To achieve a high level of accuracy continue this sequence until the results are similar for two consecutive accuracy numbers Quantities except for the surface areas are truncated to a number of significant digits consistent with the accuracy of the approximation Using Other Options The Solid One or More Surfaces and Trimmed Surface options enable you to specify a level of accuracy The higher
28. under the property sheet Location Done 5 In response to the MODEL ent prompt in the command line select the mass point 6 Select Location from the property sheet menu 7 In response to the MODEL org prompt in the command line select the location about which the system will output the polar moment of inertia Physical Properties User Guide and Menu Reference 5 7 Working with Mass Points Reporting Mass Point Data In the example the origin of the cylinder is selected de 8 Select Done from the property sheet menu The system reports the mass point data in the text window VALUES ARE GIVEN WITH RESPECT TO MODEL SPACE COORDINATES Tag no tag selected VOLUME 23 13274 MASS 23 13274 CENTROID x O20 Yo S 120 Bos 0 0 FIRST MOMENTS MYZ 0 0 MXZ 23 132741 MXY 0 0 MOMENTS OF NERTIA IXX 55 80973 IYY 49 932149 IZZ 55 80973 PRODUCTS OF INERTIA IXY 0 0 IXZ 0 0 IYZ 0 0 POLAR MOMENT OF INERTIA 80 775804 Reporting a Moment of Inertia about an Axis The following example reports mass point data and the moment of inertia and radius of gyration about a specified axis 1 Select the Verify icon from the top bar 2 Select the MASS PROPERTIES option from the menu 5 8 Physical Properties User Guide and Menu Reference Working with Ma
29. which you want to determine the mass properties of the object is different from the Top Cplane of the part Select the Apply menu panel to process property sheet selections A menu replaces Apply on the property sheet In response to prompts appearing in the command line enter the information using the property sheet menu options When finished select Done from the property sheet menu Reporting Detailed Information The following are three examples of output using the Generate Detailed Reports property sheet option 1 Save Data to Filename option not specified output appears in text window DATE Fri Jul 26 10 10 10 1996 PART NAME users mvalenti parts testpart PART UNIT mm VALUES ARE GIVEN WITH RESPECT TO COORDINATE SYSTEM OF CPLANI USER1 ORIGIN IN MODEL Gl EL SPACE 250 0 150 0 100 0 XAXIS VECTOR IN MODEL SPACE 0 0 0 0 1 0 YAXIS VECTOR IN MODEL SPACE 0 0 1 0 0 0 ZAXIS VECTOR IN MODEL SPACE 1 0 0 0 0 0 5 4 Physical Properties User Guide and Menu Reference Working with Mass Points Reporting Mass Point Data Mass Point y Description TRON_16500 HARD Tag MPL ASSOCIATE MIP 4 TAG SOL1 LAYER 10 DENSITY VOLUME MASS SURFACE AREA CENTROID X FIRST MOMENTS MYZ 4 63120e 11 MOMENTS OF NERTIA IXX 2 2e 15 IYY D SOLID
30. 2 Mxz 119 6224212 Mxy 119 6224212 MOMENTS OF NERTIA Ixx 647 4808349 Iyy 647 4808349 Izz 647 4808349 PRODUCTS OF NERTIA Ixy 239 2448425 Ixz 239 2448425 Iyz 239 2448425 Physical Properties User Guide and Menu Reference B 3 Improving Mass Properties and Volume Calculations The Cross Sections Method The Cross Sections Method If you decide that the cross sections method is the best alternative there are several things to keep in mind for best results First this method is designed to approximate the mass properties of an object whose cross sections do not change much from one to the next If the geometry changes quickly over some region of the object include many cross sections from that region And if the object has a sudden jump in the area or shape of the cross sections at some point see Figure B 2 you will obtain better results by doing the calculation in two steps 1 Calculate up to the jump 2 Calculate from there onward Then you can merge the mass points to find the mass properties of the whole object Figure B 2 Object with a Step Change in Geometry B 4 Physical Properties User Guide and Menu Reference Improving Mass Properties and Volume Calculations The Cross Sections Method Second the accuracy of results obtained with the cross sections method depends on the number of cuts cross sections used To illustrate this effect mass properties are calculated on the object sho
31. 227 7013 OCT 88 or Commercial Computer Software Restricted Rights at FAR 52 227 19 c 1 2 SUN 87 as applicable 02202007 Parametric Technology Corporation 140 Kendrick Street Needham MA 02494 USA Table of Contents Preface Related Documents vii Book Conventions vii Window Managers and the User Interface viii Online User Documentation ix Online Command Help xX Printing Documentation X Resources and Services X Documentation Comments xi Getting Started Overview of Physical Properties Functions 1 2 Explicit Environment 1 2 Numeric Accuracy 1 2 1 3 1 4 The Mass Point Parametric Environment Object Types 1 4 Requirements for Two Dimensional Objects 1 5 Requirements for an Implied Surface of Revolution 1 6 Requirements for an Implied Tabulated Cylinder 1 7 Object Defined by Cross Sections 1 7 Accuracy of the Cut and Sum Method 1 7 Requirements 1 8 Using Physical Properties 1 9 Physical Properties User Guide and Menu Reference Contents iii Preliminary Procedures 1 9 Physical Properties Options 1 9 Calculating Area 1 10 Calculating Volume 1 11 Calculating Mass Properties 1 12 Working with Mass Points 1 13 Calculating Center of Gravity 1 14 Listing Mass Points 1 15 Extracting Parametric Mass Properties Data 1 16 Restrictions 1 17 Calculating Mass Properties 1 17 Calculating Areas Gener
32. 81634 Reporting Moments of Inertia about Principal Axes The following example reports mass point data and the principal axes for a specified location 1 Select the Verify icon from the top bar 2 Select the MASS PROPERTIES option from the menu 3 When the property sheet appears select the Principal axes option Physical Properties User Guide and Menu Reference Working with Mass Points Reporting Mass Point Data In the example the axes display length is 2 units default Polar Ax1 5 Principal axes Length 2 00000 A ME oo ec Report Units Density Unit Lb in3 Apply 4 Select Apply The following menu appears under the property sheet Location Done 5 In response to the MODEL ent prompt in the command line select the mass point 6 Select Location from the property sheet menu 7 In response to the MODEL org prompt in the command line select the location at which the system will output the principal axes Physical Properties User Guide and Menu Reference 5 11 Working with Mass Points Reporting Mass Point Data In the example the origin of the cylinder is selected d2 8 Select Done from the property sheet menu The system displays the principal axes as temporary graphics and reports the mass point information in the text window VALUES ARE G
33. Each Object requests the creation of a mass point entity for each entity whose center of gravity is calculated You can specify the layer number for all new mass points created The default is the currently selected layer Selecting Create Composite Mass Point requests the creation of a mass point entity for the accumulated center of gravity You can specify the layer number for the net mass point created The default is the currently selected layer 6 6 Physical Properties User Guide and Menu Reference Calculating Center of Gravity Calculating Center of Gravity Error Messages Select Send Error Messages to Screen to display messages Deselect it to turn off messages The default is to printer error messages Physical Properties User Guide and Menu Reference 6 7 Appendix A system Messages This appendix is a reference guide for standard system messages Each message listed in this appendix is followed by the input command string to which the system is responding A short descriptive paragraph is also provided to further explain certain entries e Nonalphabetical Messages e Alphabetical Messages Physical Properties User Guide and Menu Reference A 1 System Messages Nonalphabetical Messages Nonalphabetical Messages 2 D AND 3 D MASS POINTS INCOMPATIBLE COMMAND ABORTED MERGE MPOINT A 2 Physical Properties User Guide and Menu Reference system M
34. IVEN WITH RESPECT TO MODEL SPACE COORDINATES Tag no tag selected VOLUME 23 13274 MASS 23 13274 CENTROID X 0 0 Y 1 0 Z 0 0 PRINCIPAL AXES 1 KX 1 0 Y 0 0 Z 0 0 2 X 0 0 Y QO Zi 000 3 XMS ORO YoS 0n 0 26S 0 PRINCIPAL AXES ANGLES OF ROTATION RADIANS J 0 0 2s O00 3 0 0 MOMENTS OF INERTIA ABOUT PRINCIPAL AXES 1 55 80973 2 49 932149 3 55 80973 5 12 Physical Properties User Guide and Menu Reference Working with Mass Points Inserting Mass Point Data Inserting Mass Point Data You can manually create a mass point entity with known values supplied by you or read from a text file The system checks the values for consistency before inserting the mass point Please note You can also automatically calculate these values based on the selected solid surface etc using the Calculate Physical Properties menu The Calculate Physical Properties menu also enables you to create an associative relationship between the mass point and the source geometry 1 Select the Physical Properties icon from the Model task set to display the Physical Properties menu Associative Wess Points f Zancel Physical Properties User Guide and Menu Reference 5 13 Working with Mass Points Inserting Mass Point Data 2 Select the Mass Point icon from the Physical Properties palette to display the ran wa E r J E m E following property sheet Mass Points Fro
35. MPOINT ERROR IN UPDATING MASS POINT MIP MAINTAINING PREVIOUS DATA UPDATE MPOINT ERROR OCCURRED DURING CREATION OF MASS POINT ENTITY CALCULATE AREA CALCULATE MPROPERTIES CALCULATE VOLUME ILLEGAL AXIS PLEASE TRY AGAIN The axis must be in the same plane as the curves but must not intersect CALCULATE MPROPERTIES CALCULATE VOLUME ILLEGAL DATA INSERT MPOINT b LAST BOUNDARY IS NOT CONNECTED PLEASE TRY AGAIN CALCULATE AREA CALCULATE MPROPERTIES CALCULATE VOLUME LAST LOCATION ENTERED IS IGNORED A 4 Physical Properties User Guide and Menu Reference system Messages Alphabetical Messages You have tried to enter more than the maximum number of mass points that may be inserted INSERT MPOINT M MASS OF NEW POINT FOUND TO BE NEGATIVE NO POINT CREATED MERGE MPOINT MASS OF NEW POINT FOUND TO BE ZERO NO POINT CREATED MERGE MPOINT MASS OF NEW POINT NOT GREATER THAN ZERO INSERT MPOINT MASS POINT MI
36. P HAS BEEN UPDATED UPDATE MPOINT MASS POINT NO lt N gt HAS BAD SECOND MOMENT DATA DATABASE FOR THIS MASS POINT IS NOT CHANGED CHANGE MPOINT MASS POINT NO lt N gt IS INCOMPATIBLE WITH SELECTED MODIFIERS DATABASE FOR THIS MASS POINT IS NOT CHANGED You may be trying to change a 3 D property on a 2 D mass point CHANGE MPOINT N NEW MASS POINT HAS BAD SECOND MOMENT DATA INSERT MPOINT NO UNIT CONVERSION CAN BE PERFORMED THERE IS NO UNIT ASSOCIATED TO THE SELECTED MASS POINT MIP LIST MPOINT Physical Properties User Guide and Menu Reference A 5 System Messages Alphabetical Messages LUNIT and or WUNIT modifiers have been entered but a Mass Point with no unit has been selected NO ROOM FOR MORE INPUT COMMAND CONTINUES WITH DATA INPUT SO FAR You may have been trying to merge too many mass points MERGE MPOINT NOT ALL MASS POINTS SELECTED HAVE SECOND MOMENTS DATA NEW MASS POINT CREATED WILL NOT HAVE SECOND MOMENTS DATA You may be merging incompatible mass points MERGE MPOINT NOT ALL MASS POINTS SELECTED HAVE SURFACE AREA DATA MISSING SURFACE AREA ASSUMED TO BE ZERO MERGE MPOINT NOT ENOUGH MASS POINTS SPECIFIED MINIMUM IS TWO MERGE MPOINT NOT ENOUGH ROOM IN THE SCRATCH DATA BASE INSERT MPOINT LIST M
37. POINT SOURCE MASS POINT UID BELONGING TO COMPONENT ID NOT FOUND UPDATE MPOINT The viewed in source mass point used in the MERGE MPOINT ADD ASSOCIATIVE operation is no longer present in the component SPECIFIED CPLANE HAS YET TO BE DEFINED Physical Properties User Guide and Menu Reference system Messages Alphabetical Messages CHANGE MPOINT INSERT MPOINT LIST MPOINT SPECIFIED TAG NAME ALREADY EXISTS MERGE MPOINT T THE LAST BOUNDARY HAS BEEN DELETED lt N gt BOUNDARIES REMAIN CALCULATE AREA CALCULATE MPROPERTIES CALCULATE VOLUME THE SELECTED MASS POINT WAS GENERATED BY MERGE MPOINT ADD FROM N MASS POINTS MARK MPOINT TWO POINTS NEEDED PLEASE TRY AGAIN CALCULATE MPROPERTIES CALCULATE VOLUME U UNABLE TO BACKSPACE ONE BOUNDARY Abort and start again CALCULATE AREA CALCULATE MPROPERTIES CALCULATE VOLUME UNABLE TO BACKSPACE ONE SECTION Abort CALCULATE MPROPERTIES UNABLE TO RETRIEVE N1 OF N VIEWED IN SOURCE MASS POINTS MERGED INTO MASS POINT MIP Physical Properties User Guide and Menu Reference A 7 System Messages Alphabetical Messages UPDATE MPOINT The viewed in source mass point used in the MERGE MPOINT ADD
38. Physical Properties User Guide and Menu Reference CADDS 5 15 0 DOC38126 009 Parametric Technology Corporation Copyright 2007 Parametric Technology Corporation All Rights Reserved User and training guides and related documentation from Parametric Technology Corporation and its subsidiary companies collectively PTC is subject to the copyright laws of the United States and other countries and is provided under a license agreement that restricts copying disclosure and use of such documentation PTC hereby grants to the licensed software user the right to make copies in printed form of this documentation if provided on software media but only for internal personal use and in accordance with the license agreement under which the applicable software is licensed Any copy made shall include the PTC copyright notice and any other proprietary notice provided by PTC Training materials may not be copied without the express written consent of PTC This documentation may not be disclosed transferred modified or reduced to any form including electronic media or transmitted or made publicly available by any means without the prior written consent of PTC and no authorization is granted to make copies for such purposes Information described herein is furnished for general information only is subject to change without notice and should not be construed as a warranty or commitment by PTC PTC assumes no responsibility or liability fo
39. Window 11 Select Done from the property sheet menu The system performs the calculations subtracting the area of the holes from the area of the square and reports the results in the text window AREA 78 064227282735 CENTROID X 0 02759424437445 Y 0 01876422252637 Z 0 0 2 8 Physical Properties User Guide and Menu Reference Calculating Areas Calculating an Area Defined by a Polygon Window Calculating an Area Defined by a Polygon Window The following example calculates the area bounded by a polygon window and stores the results in a mass point 1 Select the Physical Properties icon from the Model Taskset on the side bar 2 Select the Calculate Area icon from the menu 3 When the property sheet appears select the Calculate Polygon Window Area icon 4 Select the options you want and enter necessary information In the example the chosen option is to create a mass point 5 Select Apply The following menu appears on the property sheet 6 In the graphics window define a polygon window by selecting locations to enclose the area you want to calculate The system connects the first and last locations to create a bounded area You must select a minimum of three locations Physical Properties User Guide and Menu Reference 2 9 Calculating Areas Calculating an Area Defined by a Polygon Window 7 Select Done from the property sheet menu ADDS Graphics Window T
40. You can not break a merged mass point association by selecting one of it s source mass point To break a merged mass point association you must select the merged mass point itself When you select this icon from the Physical Properties submenu you are prompted to select one or more entities to dissociate Select the Done option on the Utilities menu or press the Return key to process the command You are prompted to confirm the dissociation Respond as prompted to break the selected associations The following conditions exist e When a geometric or merged mass point is deleted one of the following message appears The Mass Point MIP is now non associated to solid or tsurface MIP The Merged Mass Point MIP is now non associated e When a geometric mass point is dissociated the following message appears The Mass Point MIP is now non associated to solid or tsurface MIP e When you select a non associated mass point solid or tsurface the following message appears No Mass Point Solid or Tsurface is associated with entity MIP nothing to dissociate e When you select a source mass point the following message appears The Mass Point MIP is a source Mass Point It will not be dissociated Physical Properties User Guide and Menu Reference 5 27 Working with Mass Points Deleting Mass Points and Associated Entities Deleting Mass Points and Associated Entities
41. al Area Calculation Procedures 2 2 Calculating Combined Areas 2 5 Calculating an Area with Holes 2 7 Calculating an Area Defined by a Polygon Window 2 9 Calculating Volumes General Volume Calculation Procedures 3 2 Calculating the Volume of a Projected Object 3 7 Calculating the Volume of a Rotated Object 3 10 Calculating a Volume Using Cross Sections 3 13 Calculating Mass Properties General Mass Properties Calculation Procedures 4 2 Projection Along an Axis 4 3 Rotating a Boundary About an Axis 4 4 Using a Series of Cross Sections 4 5 Using a Solid 4 6 Contents iv Physical Properties User Guide and Menu Reference Using a Volume Enclosed By One or More Surface 4 6 Using a Trimmed Surface 4 6 Using Other Options 4 7 Calculating the Mass Properties of a Projected Object_ lt lt 4 10 Calculating the Mass Properties of a Rotated Object 4 13 Calculating Mass Properties Using Cross Sections 4 17 Calculating Mass Properties Using a Solid and Associativity _____ 4 22 Replacing an Existing Associated Mass Point 4 23 Updating Associated Mass Points 4 23 Merging Mass Points 4 23 Working with Mass Points Reporting Mass Point Data 5 2 Reporting Detailed Information 5 4 Reporting a Polar Moment of Inertia 5 7 Reporting a Moment of Inertia about an Axis 5 8 Reporting Moments of Inertia about Principal Axes 5 10 Ins
42. al Properties User Guide and Menu Reference Calculating Mass Properties Calculating Mass Properties Using a Solid and Associativity If the association fails for any reason the mass point will be created without any association relationship and the following message will appear Error in associating Solid Tsurf to Mass Point creating a non associated Mass Point Replacing an Existing Associated Mass Point If the selected Solid or Tsurf already has an associated mass point it will be deleted and a new one will be recomputed and associated to the selected Solid or Tsurf All the data stored into the old associated mass point will be removed along with the old associated mass point If the existing associated mass point is itself related to another existing merged mass point i e it is a source mass point used in a previous MERGE MPOINT operation the merged association not the mass properties are also updated by replacing the old MIPTR with the MIPTR of the new created mass point This is repeated until all associations are updated Updating Associated Mass Points See Updating Associative Mass Point Chapter 5 to learn about updating he physical properties information within an associative mass point Merging Mass Points See Merging Mass Point Data Chapter 5 to learn about merging mass points to determine composite values of multiple objects Physical Properties User Guide and Menu Reference 4 23 Chapter
43. ay remain on the screen Z 1 Select the Physical Properties icon from the Model Taskset on the side bar ieee P 2 Select the Calculate Volume icon from the menu 3 When the property sheet appears select the Cross Sections Method icon Physical Properties User Guide and Menu Reference 3 13 Calculating Volumes Calculating a Volume Using Cross Sections 4 Select the options you want and enter the necessary information In the example the chosen options are e Subtract hole s e Calculate surface area e Calculate 6 cross sections e Starting layer is 4 e Increment the layer by 2 Calculate Volume Done 6 In the graphics window select the boundaries of the first cross section 7 Select the Select hole option from the property sheet menu 3 14 Physical Properties User Guide and Menu Reference Calculating Volumes Calculating a Volume Using Cross Sections 8 In the graphics window select the boundaries of the hole in the first cross section Cross Section 1 Eottom of cylinder 9 For each successive cross section repeat the following steps a Select Next cross section on the property sheet menu b In the graphics window select the boundaries of the next cross section e Select hole on the property sheet menu d In the graphics window select the boundaries of the hole in the identified cross section Cros Section 2 Physical Properties User Guide and Menu Reference 3 15 Calculat
44. d Apply The following options are available for calculating mass properties Projection Along an Axis This option enables you to calculate physical properties by projecting the boundaries of an object along an axis This axis must not lie in the plane of the boundaries All boundaries must be coplanar and cannot be self intersecting Physical Properties User Guide and Menu Reference 4 3 Calculating Mass Properties General Mass Properties Calculation Procedures If you select the projection method to calculate mass properties the following options are available Option Description Start depth 0 0000 Specifies the distance from the plane of the boundaries to the bottom low boundary of the projected object default is 0 0 measured along the axis from the plane of the boundaries End depth 1 0000 Specifies the distance from the plane of the boundaries to the top high boundary of the projected object default is 1 0 measured along the axis from the plane of the boundaries The terms related to projection methods for calculating mass properties are illustrated in the following figure Figure 4 1 Projection Methods for Calculating Mass Properties Projection ans r w Epetd solid after High boundany A projection End depth _ i Closed boundan Rotating a Boundary About an Axis This option enables you to calculate mass properties by rotating the boundaries of an object about a specified
45. e new merged mass point and all selected source mass points See Merging Mass Point Data for more information Tag Assigns a tag to the mass point Tag names are limited to six alphanumeric A Z 0 9 characters Merging Mass Points Sample Session The following example creates a mass point whose values represent the sum of two merged mass points Select the Physical Properties icon from the Model task set on the side bar 2 Select the Mass Point icon from the menu i When the property sheet appears select the Merge option A Select the Add option Physical Properties User Guide and Menu Reference 5 19 Working with Mass Points Merging Mass Point Data 5 Select the Associative option Insert Replace original mass points Change 6 Select Apply 7 In the graphics window select the mass points that you want to merge New mass point created contains sum of data contained in mass points selected 8 Select Done from the Utilities menu 5 20 Physical Properties User Guide and Menu Reference Working with Mass Points Merging Mass Point Data Listing Mass Point Data Create a file to list the values stored in the two source mass points and the resultant merged mass point used in the previous example 1 Select the Verify icon from the top bar 2 Select the MASS PROPERTIES option from the menu Polar Axis Principal ases fei I EREI set sA a a E a
46. e property sheet appears select the Insert option 4 Select the options you want and enter the necessary information In the example the chosen options are e Area of 10 e Mass of 20 e X moment of inertia Ixx of 21 e XY production of inertia Ixy of 22 Physical Properties User Guide and Menu Reference 5 15 Working with Mass Points Inserting Mass Point Data e Y moment of inertia lyy of 23 Insert Volume 00000 EE ei pra E 00000 T h AM q Hy 00000 00000 ive to mass point Density Unit Lb ins 5 Select Apply 6 In the graphics window select mass point locations 7 Select Done from the Utilities menu The system creates mass point symbols at the selected locations 5 16 Physical Properties User Guide and Menu Reference Working with Mass Points Merging Mass Point Data Merging Mass Point Data You can create a mass point whose values represent the sum or difference of two or more existing mass points You can optionally specify that the merged mass point be associative to the selected source mass points Use the Merge option to calculate the mass properties of an object that is the sum or difference of two or more other objects For example to calculate total weight merge the masspoints of all models within an assembly Source mass points can be optionally deleted Any mass points can be a source mass point of one or several merge operations However you can only m
47. ections which are calculated separately and then summed to approximate the physical properties of the object The boundary of each bounded region consists of one or more of the following entities e Lines e Arcs e Conics e B splines Strings e Curve poles e Nodal lines An object s boundary can enclose either a positive solid or a negative hole region Requirements for Two Dimensional Objects To calculate physical properties for two dimensional objects 1 All boundary curves must lie in the same plane 2 The number of closed boundaries solid and holes is not limited but the number of entities in each boundary must be fewer than 300 Please note An example Physical Properties User Guide and Menu Reference 1 5 Getting Started Overview of Physical Properties Functions Requirements for an Implied Surface of Revolution To calculate physical properties for an implied surface of revolution 1 All boundary curves must lie in the same plane 2 The axis of revolution also must lie in the same plane as the boundary curves and cannot intersect the curves although the axis can touch be tangent to the curves 3 The number of closed boundaries solid and holes is not limited but the number of entities in each boundary must be fewer than 300 Please note Because all physical properties calculations are based on the defining curves it is not necessary to create any surfaces or solids
48. ections Method Physical Properties User Guide and Menu Reference B 1 Improving Mass Properties and Volume Calculations The Projection and Rotation Method The Projection and Rotation Method You can frequently recognize portions of an object for which the projection and rotation methods are applicable For example the object shown in the Figure B 1 consists of a 4 inch cube with a 1 inch radius spherical hole in the center Boundaries that can be projected and rotated to generate a cube with a spherical hole in the center are shown on the left The geometry after projection and rotation of the boundaries is shown on the right Figure B 1 Cube with a Spherical Center While this object may appear to be a candidate for the cross sections method because it is neither a solid of projection nor a solid of rotation notice that the cube is a solid of projection and the sphere is a solid of rotation In the following example the mass properties of each are calculated using the projection and rotation methods then the mass point of the sphere is subtracted using the Merge Mass Point option from that of the cube t n CALCULATE MPROPERTIES ROTATE TAG M1 PLEASE DIGITIZE TWO POINTS TO DEFINE ROTATION AXIS MODEL loc END dd PLEASE ENTER SOLID BOUNDARY 1 dd PLEASE ENTER SOLID BOUNDARY 2 VOLUME 4 1887903 MASS 4 1887903
49. erefore use either the projection or rotation methods whenever possible If the cross sections method must be used specify as many cuts as possible near the region of the part where extreme changes of geometry take place See Appendix B Improving Mass Properties and Volume Calculations for further detail on the cross sections method Physical Properties User Guide and Menu Reference 3 5 Calculating Volumes General Volume Calculation Procedures The following options are available with any method Option Mass point Hole Surface area Density 1 000000 Tag Description Creates in Model mode only a mass point symbol at the centroid center of mass of the given boundaries to store the results of the calculations Specifies one or more hole boundaries the negative area to subtract from the defined bounded area the positive area The total negative hole area is subtracted from the total positive area to calculate the resulting area Calculates the outermost surface area of the object When using the rotation or projection method it is the surface area generated by the first boundary selected for the cross sections method it is the area of a surface interpolated between the first boundaries of each section Specifies the density of the object default is 1 00000000 Assigns a tag to the mass point Tag names are limited to six alphanumeric A Z 0 9 characters 3 When finis
50. erge mass points of the same type those containing two dimensional data or those containing three dimensional data You can merge both associative and non associative mass points You can also merge previously merged masspoints with other mass points If some mass points contain second moment data while others do not the new mass point will not contain second moments If some mass points contain surface area data while others do not the missing values are assumed to be zero Please note Ifa merge would result in meaningless values such as negative volume the system does not perform the operation Conditions of Associative Merging If you use the Associative option while merging the mass points of solids Tsurfs an association is created between the merged mass point and its source mass points A mass point can be a source mass point of one or several merged associations each association is maintained If the existing associated merged mass point is already related to another merged mass point i e it is a source mass point used in a previous MERGE MPOINT operation the merged association not the Mass Properties are also updated by replacing the old MIPTR with the MIPTR of the new created merged mass point This is repeated until all associations are updated If you use the Replace original mass points option for deleting the selected source mass points the merged mass point is created without any association relationship
51. erting Mass Point Data 5 13 Inserting Mass Points Sample Session 5 15 Merging Mass Point Data 5 17 Conditions of Associative Merging 5 17 Merge Options 5 18 Merging Mass Points Sample Session 5 19 Listing Mass Point Data 5 21 Changing Mass Point Data 5 22 Changing Associative Mass Points 5 23 Manipulating Associative Mass Points 5 23 Updating Associative Mass Point 5 24 Highlighting Mass Point Associations 5 26 Breaking Mass Point Associativity 5 27 Deleting Mass Points and Associated Entities 5 28 Physical Properties User Guide and Menu Reference Contents v Calculating Center of Gravity Overview of Calculating Center of Gravity Calculations Performed Calculation Output Mass Points Calculations for Steel Inserted with Various Packages Calculating Center of Gravity Inout Weight Filename Mass Table Format Header Line Keywords Output Report Filename Output Report Weight Units Properties Mass Points Error Messages system Messages Nonalphabetical Messages Alphabetical Messages Improving Mass Properties and Volume Calculations The Projection and Rotation Method The Cross Sections Method Cross Sections Method Calculations 6 2 6 2 6 2 6 3 6 4 6 4 6 5 6 6 6 6 6 6 6 7 A 2 A 3 B 2 B 4 Contents vi Physical Properties User Guide and Menu Reference Preface The Physical Properties User Guide and Menu Refere
52. essages Alphabetical Messages Alphabetical Messages A AREA AND SURFACE AREA ARE INCOMPATIBLE MODIFIERS TRY AGAIN CHANGE MPOINT AREA OF NEW MASS POINT NOT GREATER THAN ZERO INSERT MPOINT AT LEAST THREE DIGITIZES ARE NEED AGAIN T iD FOR CLOSED BOUNDARY PLEASE TRY CALCULATE AREA CALCULATE MPROPERTIES CALCULATE VOLUME C COMPONENT ID NOT LOADED INTO ASSEMBLY CANNOT RETR MASS POINT UID a E SOURCE UPDATE MPOINT The component containing a viewed in source mass point used in MERGE MPOINT ADD ASSOCIATIVE is no longer present in the current assembly CROSS SECTION lt N gt HAS BEEN DELETED PLEASE RE ENTER IT CALCULATE MPROPERTIES CALCULATE VOLUME DENSITY MAY NOT BE COMBINED WITH OTHER MODIFIERS TRY AGAIN CHANGE MPOINT Physical Properties User Guide and Menu Reference A 3 System Messages Alphabetical Messages E ERROR CONDITION ENCOUNTERED COMMAND ABORTED CHANGE MPOINT MERGE MPOINT ERROR CONDITION ENCOUNTERED IN MPTDATA PROGRAM TERMINATES MERGE
53. following message appears Mass Point MIP is associative its properties cannot be changed Manipulating Associative Mass Points You cannot translate rotate mirror or revise an associative mass point without using the Copy option If you attempt to the following message appears Mass Point MIP is associative its properties cannot be changed Physical Properties User Guide and Menu Reference 5 23 Working with Mass Points Updating Associative Mass Point Updating Associative Mass Point To update an associative mass point when either its source geometry or source mass points have changed you must use the Update Mpoint function You can select a solid tsurf to update it s associated mass point or you can select the geometrically associated mass point itself You can also select a merged mass point to update it based on the most current state of its associated source mass points Lastly you can request that all associative mass points be updated The two Update menu options obtained from the Physical Properties submenu are shown below The first enables you to select specific associative mass point or solids tsurfs within the active part The second acts on all associative mass points within the active part Each selected associative mass point is deleted and a new one created based on the following e The Layer Color Tag Properties Thickness Thicken direction and Density are retrieved from old mass
54. h of 12 feet you can insert the property MTYPE or any other text valued property with a value of A 12 In the mass table for this example specify A 12 in the IDENTIFIER column a weight value in the WEIGHT column and the local center of gravity of the member in the XOFFSET YOFFSET and ZOFFSET columns Then specify the MTYPE property value Physical Properties User Guide and Menu Reference 6 3 Calculating Center of Gravity Calculating Center of Gravity Calculating Center of Gravity 1 Select the Physical Properties icon from the Model Taskset 2 Select the Calculate Center of Gravity icon from the Physical Properties menu The property sheet for Calculate Center of Gravity appears as shown below Ca culate Canter of Geayizy Inpu eight Filerare HASS TAELE a Report ilen CG OUTPUT Curput Weigh Urits Incluce Property Valuz in Raport Creare Macs Poort Fer Eac bject Create Compesite Macs Proet _ Senc E ror Mess Reresn apply Input Weight Filename This is the name of the text file that contains a table that cross references property values to weights or weight length for pipes ducts and entities with length The mass table contains the information from which all weight and center of gravity calculations are performed The default name is MASS TABLE 6 4 Physical Properties User Guide and Menu Reference Calculating Center of Gravity Calculating Center of Gravity
55. he system calculates the area enclosed by the polygon window and its center of mass Then it creates a mass point symbol at the calculated centroid position to store the results and reports the results in the text window AREA 84 696614718486 CENTROID X 0 01835714617692 Y 0 03176306845243 Z 0 0 Physical Properties User Guide and Menu Reference Chapter 3 Calculating Volumes This chapter provides instructions for calculating the volumes of objects using the projection rotation and cross sections methods e General Volume Calculation Procedures e Calculating the Volume of a Projected Object e Calculating the Volume of a Rotated Object e Calculating a Volume Using Cross Sections Physical Properties User Guide and Menu Reference 3 1 Calculating Volumes General Volume Calculation Procedures General Volume Calculation Procedures You can compute the volume of an object defined by one of the following methods e The projection of planar boundaries along an axis e The rotation of planar boundaries about an axis e A series of planar cross sections Optionally you can also compute an object s surface area You can calculate volumes for models whose boundaries consist of e Lines e Arcs e Conics e B splines e Strings e Nodal lines Nlines To calculate the volume 1 Select the Physical Properties icon from the Model Taskset on the side bar 3 2 Physical Properties User G
56. hed choosing the options you want select Apply A menu appears on the property sheet with options related to those chosen on the property sheet 4 In response to prompts appearing in the command line enter the information as directed using the menu options 5 When finished select Done from the property sheet menu The system performs the calculations and reports the results in the text window 3 6 Physical Properties User Guide and Menu Reference Calculating Volumes Calculating the Volume of a Projected Object Calculating the Volume of a Projected Object The following example calculates the volume and surface area of a cylinder with a square hole using the projection method 1 Select the Physical Properties icon from the Model Taskset on the side bar 2 Select the Calculate Volume icon from the menu 3 When the property sheet appears select the Projection Method icon That is the top most icon Physical Properties User Guide and Menu Reference 3 7 Calculating Volumes Calculating the Volume of a Projected Object 4 Select the options you want and enter the necessary information Calculate Volume Apply In the example the chosen options are to Calculate the surface area Subtract hole s Project the end depth to 2 inches a Select Apply The following menu appears on the property sheet Done 6 In response to the MODEL loc prompt in the command line select tw
57. ical Properties property sheet displays the following property sheet Mass Points d From file Area 1 000000 gt Volume Mass f Ixx n Ixy j a Relative to mass poin Cance The options on this property sheet allow you to e Insert mass point data by creating a mass point containing physical property values which you supply e Merge mass point data by adding or subtracting the values stored in two or more mass points e Change mass point data by modifying existing mass point data values Directions for inserting merging and changing mass point data are in Chapter 5 Working with Mass Points Physical Properties User Guide and Menu Reference 1 13 Getting Started Using Physical Properties Calculating Center of Gravity Selecting the Calculate Center of Gravity icon displays the following property sheet C3 ulate Canter of Graviz Input eight Filerara HASS TAELE Cuzput Report Filen 0G OUTPUT Cucput Weigh Urits Incluce Property Waluz in Raport Create Mass Poort Fer Ezer Jhject Create Composite Mass Poort senc Error Mess I aerez apply If you select Include Property Value in Report you can specify a property If you select Create Mass Point For Each Object you can specify a layer If you select Create Composite Mass Point you can specify a layer The default is to send error messages to the screen Information about the data you can enter in this property sheet is i
58. ies and Volume Calculations The Cross Sections Method Figure B 5 The Calculated Volume Plotted Against the Inverse of the Number of Cuts Humber of steps Number of sections 1 Volume i__ Ho of sections Volume L omn n te us 1 Nunber of sections As a further illustration the graphical technique shown earlier in Calculated Volume Plotted Against the Number of Cuts is repeated for the geometry in the following figure The volumes are plotted and listed in Calculated Volume Plotted Against the Number of Cuts later in this appendix The convergence of the volume to the true answer 45 9587 is seen as more cuts are used Physical Properties User Guide and Menu Reference B 7 Improving Mass Properties and Volume Calculations The Cross Sections Method Figure B 6 A Pyramid Section with a Center Hole Actually this geometry is an example of the situation discussed at the beginning of this appendix where the cross sections method alone is not the best technique to use Because the cylindrical hole in the center of the frustum of the pyramid is a tabulated cylinder you can obtain more accurate results by using the cross sections method on the frustum of the pyramid and the projection method on the cylindrical hole Afterward you can find the mass properties of the complete object by merging subtracting the mass point of the cylinder and the mass point of the frustum of the pyramid W
59. ified with Save Data in Decimal Format also specified decimal format DATE 22 07 96 ULEN mm UWGT Kg PART NAME users mvalenti parts testpart DESCR IRON_16500 HARD TAG MP1 ASSMIP 4 ASSTAG SOL1 ASSLAY 10 CPL USER1 CPLOX 250 000000 CPLOY 150 000000 CPLOZ 100 000000 CPLXX 000000 CPLXY 000000 CPLXZ 1 000000 CPLYX 000000 CPLYY 1 000000 CPLYZ 000000 CPLZX 1 000000 CPLZY 000000 CPLZZ 000000 DENS 0 00000276 VOL 255999999 999938 SAREA 11999999 999995 MASS 1413 787654 CMX 1809 064134 CMY 1385 515143 CMZ 44 375000 FMX 463120300000 000 FMY 354691800000 000 FMZ 11360000000 0000 IXX 2172464E 16 IYY 1297764E 16 IZZ 3468752E 16 IXY 2315693E 15 IXZ 2055096H 14 IYZ 1573945H 14 ITALY 5 6 Physical Properties User Guide and Menu Reference Working with Mass Points Reporting Mass Point Data Reporting a Polar Moment of Inertia The following example reports the data stored in a mass point and the polar moment of inertia for a specified location 1 Select the Verify icon from the top bar 2 Select the Mass Properties option from the menu 3 When the property sheet appears select the Polar option default Ax1S Principal axes Bit a imate sls eas LL uu lt lt 4 Report Units Density Unit Lb in3 Apply 4 Select Apply The following menu appears
60. ing Volumes Calculating a Volume Using Cross Sections The steps are repeated for the third cross section Cross Section The steps are repeated for the fourth cross section Cross Section 4 The steps are repeated for the fifth cross section Cross Section 5 3 16 Physical Properties User Guide and Menu Reference Calculating Volumes Calculating a Volume Using Cross Sections The steps are repeated for the last cross section 10 When finished select Done from the property sheet menu The system calculates the volume and surface area and reports the results in the text window VOLUME 45 9467239 SURFACE AREA 89 0659561 Physical Properties User Guide and Menu Reference 3 17 Chapter 4 Calculating Mass Properties This chapter provides instructions for calculating the mass properties of objects using the projection rotation and cross sections methods General Mass Properties Calculation Procedures Calculating the Mass Properties of a Projected Object Calculating the Mass Properties of a Rotated Object Calculating Mass Properties Using Cross Sections Calculating Mass Properties Using a Solid and Associativity Physical Properties User Guide and Menu Reference 4 1 Calculating Mass Properties General Mass Properties Calculation Procedures General Mass Properties Calculation Procedures You can compute the following mass properties of an object e Volume
61. ing the area of one or more holes if any exist You can calculate areas for models or drawings whose solid and hole boundaries consist of Lines Arcs Conics B splines Strings Nodal lines Nlines To calculate the area 1 2 Select the Physical Properties icon from the Model Taskset on the side bar to display the Physical Properties palette as shown below Paysical Properti GUBE Select the Calculate Area icon from this palette 2 2 Physical Properties User Guide and Menu Reference Calculating Areas General Area Calculation Procedures The following property sheet appears Calculate Area Mass point Hole Apply The following options are available for calculating area Option Description Calculates the area of any closed boundary default option Calculates the area of region not bounded by existing entities by defining a polygon window whose corner locations vertices create the boundary The system closes the polygon automatically connecting the first and last selected locations At least three locations are required to define a polygon window s boundary Mass point Creates in Model mode only a mass point symbol at the centroid center of mass of the given boundaries to store the results of the calculations Hole Specifies one or more hole boundaries the negative area to subtract from the defined bounded area the positive area The total negative hole
62. ith 10 sections 11 cuts of the frustum of the pyramid and use of the projection method on the cylindrical hole the volume is calculated as equal to the true answer 45 9897 B 8 Physical Properties User Guide and Menu Reference Improving Mass Properties and Volume Calculations The Cross Sections Method However the true volume is found in this example because the formulas employed in finding the volume in the cross sections method are geared toward a more exact solution for geometries that are similar to the frustum of a pyramid see Appendix C Cross Sections Method Calculations for a discussion of the formulas used Figure B 7 Calculated Volume Plotted Against the Number of Cuts Number of steps Humber of sections 1 Te answer 45 S370 Volume Thickness of No of each section sections Wolurie di 5607 it Number of sections Physical Properties User Guide and Menu Reference B 9 bee Cross Sections Method Calculations The cross sections method for calculating physical properties first calculates the moments of each cross section Then the moments of the entire object are found by summing the moments of the cross sections Two cross sections for an arbitrary object are shown below CADDS Graphics Windove Suppose these two cross sections S1 and S2 are the top and bottom cross sections of an arbitrary object Knowing the moments of S1 and S2 and the height of the object does not give yo
63. m file 1 000000 Volume Ixx Ixy Cancel You can select one of the following options when creating a mass point and inserting known mass properties data Table 5 2 Options on the Insert Mass Point Property Sheet Option Description From file Specifies the file from which mass point data is taken Area n Specifies the area value Volume Specifies the volume value If you select Area or Volume options you can enter values for any of the following options Mass Ixx x moment of inertia Ixy xy product of inertia Iyy y moment of inertia Density specify measurement units You can also designate the coordinate system that the mass property values reference by selecting a Cplane from the list of existing Cplanes Physical Properties User Guide and Menu Reference Working with Mass Points Inserting Mass Point Data If you select the Volume option you can also enter values for any of the following options e Surface area e Ixz xz product of inertia e lyz yz product of inertia e Izz z moment of inertia You can assign a tag to the system created mass point Tag names are limited to six alphanumeric A Z 0 9 characters Inserting Mass Points Sample Session The following example creates two mass points containing arbitrary data from the property sheet 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Mass Point icon from the menu w When th
64. n Chapter 6 Calculating Center of Gravity 1 14 Physical Properties User Guide and Menu Reference Getting Started Using Physical Properties Listing Mass Points 2 To report mass point data select the Query icon from the top bar Selecting the Mass Properties option from the resultant menu displays the following property sheet Polar Axis Principal axes r e ae BAe ae sA a a jE E m m E Report Units Density Unit Lb ind Apply Use this property sheet to list information stored in a mass point In addition to the data computed by mass properties calculations you can report the e Polar moment of inertia about any point e Moment of inertia about any axis e Principal axes and principal moments of inertia at any point Directions for reporting data stored in mass points are in Chapter 5 Working with Mass Points Physical Properties User Guide and Menu Reference 1 15 Getting Started Extracting Parametric Mass Properties Data Extracting Parametric Mass Properties Data While you are within the Parametric environment use the Calculate Properties option to report on various physical properties You can request a report on the following current physical properties of a solid or selected surfaces e Volume e Surface area e Mass e Centroid center of mass e First mass moment e Moments of inertia e Principal moments of inertia e Principal axes When requesting the report
65. nally save the data in a text file 5 2 Physical Properties User Guide and Menu Reference Working with Mass Points Reporting Mass Point Data Options related to reporting mass point data are available from the Query icon on the top bar When you select the MASS PROPERTIES option from the Query menu the following property sheet appears sA P a El m E E fi PEER AEE ved format Lb in Cancel Here are the options you can select on this property sheet Table 5 1 Options on the List Mass Point Property Sheet Option Polar Axis Principal axes Length 2 00000 Save data to file Description Lists the polar moment of inertia about a selected location default Lists the moment of inertia and radius of gyration about a selected axis Lists the principal axes axes of symmetry as well as the moments of inertia about those axes at selected locations Specifies the length of the principal axes display Save the mass properties data in the file named By default the file is stored in the active parts storage directory You can view the information in the file you have created at the operating system level Change to the parts storage _bed directory and display the file contents The file is created using scientific notation with 7 significant digits Physical Properties User Guide and Menu Reference 5 3 Working with Mass Points Reporting Mass Point Data Table 5
66. nce provides information and instruction for engineers who need to calculate physical properties of CADDS 5 explicit and or parametric geometry within either an active part or assembly This book assumes that you are familiar with physical properties calculations and have a working knowledge of CADDS 5 Explicit and Parametric modeling and assembly design Related Documents The following documents may be helpful as you use Physical Properties User Guide and Menu Reference e Introduction to CADDS 5 e Explicit Modeling User Guide and Menu Reference e Parametric Modeling User Guide and Menu Reference e Concurrent Assembly Mock Up User Guide and Menu Reference Book Conventions The following table illustrates and explains conventions used in writing about CADDS applications Convention Example Explanation Menu selections and options List Section option Specify Layer Indicates a selection you must make from a field menu or property sheet or a text field that you must fill in User selected graphic X dy or P1 Marks a location or entity selection in graphic location examples Physical Properties User Guide and Menu Reference vii Preface Convention Example Explanation User input in CADDS text fields and on any command line cvaec hd data param tar xvf dev rsto Enter the text in a CADDS text field or on any command line System output Binary transfer complete Indicates
67. nd Menu Reference 4 9 Calculating Mass Properties Calculating the Mass Properties of a Projected Object Calculating the Mass Properties of a Projected Object The following example uses the projection method to calculate the mass properties of a cylinder with a square hole Figure 4 2 Example for Projection Method to Calculate Mass Properites 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Calculate Mass Properties icon from the menu 3 When the property sheet appears select the Projection Method icon 4 10 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating the Mass Properties of a Projected Object 4 Select the options you want and enter the necessary information End depth 2 0000 Density 1 0000000000 _ Unit Lb zZ ind Apply In the example the chosen options are to e Calculate the surface area e Subtract one or more holes e Project the end depth to 2 inches e Create a mass point 5 Select Apply The following menu appears on the property sheet More boundaries 6 In response to the MODEL loc prompt in the command line select two locations to define the projection axis 7 In response to the following prompt in the command line select the cylinder Please Enter Solid Boundary 1 8 Select hole from the property sheet menu Physical Properties User Guide and Menu Reference 4 11 Calc
68. ne from the property sheet menu The system calculates the volume and surface area and reports the results in the text window VOLUME 45 9467239 MASS 45 9467239 SURFACE AREA 89 0659561 CENTROID X 0 0 Y 0 0 Z 2 1825222 FIRST MOMENTS Myz 0 0000014 Mxz 0 0000007 Mxy 100 279747 MOMENTS OF NERTIA 375 1889038 Izz 122 7237625 Ixx 375 1889038 Iyy PRODUCTS OF NERTIA Ixy 0 0000002 IXZ 0 0000014 Iyz 0 0000012 Physical Properties User Guide and Menu Reference 4 21 Calculating Mass Properties Calculating Mass Properties Using a Solid and Associativity Calculating Mass Properties Using a Solid and Associativity 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Calculate Mass Properties icon from the Physical Properties menu 3 When the property sheet appears select the Solid icon 4 Enable the Mass Point option 5 Enable the Associative option Calculate Physical Properti Mass point Level of accuracy 2 Unit Lb Z in3 Apply 6 Apply the property sheet 7 Select a solid 8 Select the Done option on the Utilities menu or press the Return key on the keyboard The associative mass point is created at the centroid of the solid and placed on the active layer Additionally output is sent to the CADDS dialog window 4 22 Physic
69. o locations to define the projection axis 7 In response to the following prompt in the command line select the cylinder Please Enter Solid Boundary 1 8 Select hole from the property sheet menu 3 8 Physical Properties User Guide and Menu Reference Calculating Volumes Calculating the Volume of a Projected Object 9 In the graphics window select the square s four lines in order Projection ais 10 Select Done from the property sheet menu The system reports the results in the text window VOLUME 23 1327419 SURFACE AREA 48 26548 Physical Properties User Guide and Menu Reference 3 9 Calculating Volumes Calculating the Volume of a Rotated Object Calculating the Volume of a Rotated Object The following example calculates the volume of a hemisphere with a cylindrical hole in the base using the rotation method Cylindrical hole 1 radius and 1 high 1 Select the Physical Properties icon from the Model Taskset on the side bar 2 Select the Calculate Volume icon from the menu 3 When the property sheet appears select the middle icon the Rotation Method icon Physical Properties User Guide and Menu Reference Calculating Volumes Calculating the Volume of a Rotated Object 4 Select the options you want and enter the necessary information In the example the chosen options are to create a mass point and calculate the surface area Calculate Volume Apply 5
70. of Gravity Selecting the Calculate Center of Gravity icon calculates the center of gravity for the following kinds of components e Piping e Steel e Heating Ventilating and Air Conditioning e User defined These components must have been created with packages in the Engineering Products set Calculations Performed For each component the system calculates the center of gravity with respect to a user defined reference location as well as the composite center of gravity for all entities selected You can also select mass points and factor these into the composite center of gravity Calculation Output Given a reference point Calculate Center of Gravity provides offsets from each center of gravity to the reference location These offsets are directed to a text file and listed in an output table containing e Component identifiers such as STOCKNO STEELID or other user selected property values e Weight of the component e Offset of its center of gravity from the reference point Mass Points You can also insert mass points in the database for each component s center of gravity including the accumulated center of gravity If you choose to use a mass point to represent a component you must ensure that no property lookup occurs for that component otherwise it is included twice in all calculations once using the information from the mass point and again from the lookup 6 2 Physical Properties User Guide and Menu Refe
71. or area e Mass e Centroid e First moments e Moments of inertia e Products of inertia e Surface area e Center of gravity The selected object or objects can be either explicit or parametric entities that are either viewed in that is CAMU or physically located in the active CADDS part The mass properties information is stored in a mass point which is automatically created at the centroid of the selected entity The mass point is inserted into the physically active part You can select one or more mass points to display the mass properties either in the text window or the Report Window You can create a mass point that is associative to the solid Tsurf geometry or is nonassociative To be associative the selected object must be physically located within the active part Boundaries can consist of e Lines e Arcs e Conics e B splines e Strings e Nodal lines Nlines These boundaries can represent solid regions or holes Boundary values are assigned relative to model space coordinates Physical Properties User Guide and Menu Reference Calculating Mass Properties General Mass Properties Calculation Procedures To calculate mass properties 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Calculate Physical Properties icon from the Physical Properties menu The following property sheet appears Level of accuracy 2 Density 1 0000000000 Unit Lb zZ in
72. oss sections method C 1 examples cross sections method 3 13 projection method 3 7 rotation method 3 10 methods for improving results B 1 options 3 3 procedures 3 2 Index 2 Physical Properties User Guide and Menu Reference
73. r any errors or inaccuracies that may appear in this document The software described in this document is provided under written license agreement contains valuable trade secrets and proprietary information and is protected by the copyright laws of the United States and other countries It may not be copied or distributed in any form or medium disclosed to third parties or used in any manner not provided for in the software licenses agreement except with written prior approval from PTC UNAUTHORIZED USE OF SOFTWARE OR ITS DOCUMENTATION CAN RESULT IN CIVIL DAMAGES AND CRIMINAL PROSECUTION For Important Copyright Trademark Patent and Licensing Information For Windchill products select About Windchill at the bottom of the product page For InterComm products on the Help main page click the link for Copyright 2007 For other products select Help gt About on the main menu for the product UNITED STATES GOVERNMENT RESTRICTED RIGHTS LEGEND This document and the software described herein are Commercial Computer Documentation and Software pursuant to FAR 12 212 a b OCT 95 or DFARS 227 7202 1 a and 227 7202 3 a JUN 95 and are provided to the US Government under a limited commercial license only For procurements predating the above clauses use duplication or disclosure by the Government is subject to the restrictions set forth in subparagraph c 1 i1 of the Rights in Technical Data and Computer Software Clause at DFARS 252
74. rence Calculating Center of Gravity Overview of Calculating Center of Gravity Calculations for Steel Inserted with Various Packages When calculating center of gravity the software interprets in different ways steel that has been inserted with the various Engineering Products steel packages The interpretation used is based on the following e Structural Steel Modeling SSM members are Nfigures with the STEELIDENT property of 1 Their weight is determined from the WEIGHT LENGTH column in the mass table and the length is specified by the CLINEDISP or BEAMLENGTH property The center of gravity is calculated e Structural Modeling System SMS members are identified by the BDELNAME property on the Nfigure Their weight is read from the WEIGHT column and the center of gravity is located from the center of gravity columns e Inner Hull Design IHD steel is identified by the ENTTYPE property Its weight is read from the WEIGHT column and the center of gravity is located from the local center of gravity columns e Plant Design steel is identified by the FITTYPE property with a value of 100 101 110 or 300 Its weight is read from the WEIGHT column and the center of gravity is located from the local center of gravity columns When steel members are handled as point masses you must insert a property that is unique for each cross section and length combination onto the member For example for all members of cross section type A with a lengt
75. riable in the caddsrc local file as follows setenv USE_EXP_REP_WINI DOW yes The default setting for this environment variable is no 4 8 Physical Properties User Guide and Menu Reference Calculating Mass Properties General Mass Properties Calculation Procedures The Report Window appears as follows when accessed from the UTILITY pull down menu Report Window Warning no accuracy value retrieved from Mass Point MIP 73 DATE Thu Jul 19 16 04 52 2007 PART NAME USERS CGHANTA PARTS ASDFSA DEFAULT PART UNIT IN VALUES ARE GIVEN WITH RESPECT TO MODEL SPACE COORDINATES ORIGIN IN MODEL SPACE 0 0 0 0 0 0 MAXIS VECTOR IN MODEL SPACE YAXIS VECTOR IN MODEL SPACE ZAXIS VECTOR IN MODEL SPACE Tag no tag selected DENSITY 55 0 AREA MASS CENTROID X 4 873709 Y 2 75899 2 0 0 FIRST MOMENTS Myz 268 0539 Mxz 151 744823 Mxy 0 0 Can t find desktop configuration E gen_report_win VOLUME 0 523598 In3 MASS 0 523598 Lb SURFACE AREA 3 141588 In2 CENTROID X 4 521739 Y 2 608696 Z 0 0 In FIRST MOMENTS MYZ 2 367574 MXZ 1 365908 MXY 0 0 Lb In MOMENTS OF INERTIA IXX 3 615605 IYY 10 757915 IZZ 14 321156 Lb In2 PRODUCTS OF INERTIA IXY 6 17628 IXZ 2 0 0 Lb In2 If you select the mass point option CADDS also creates it The mass point is created in the active part on the active layer Physical Properties User Guide a
76. ries 6 In the graphics window select the boundaries of the first cross section 7 Select the Select hole option from the property sheet menu 4 18 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating Mass Properties Using Cross Sections 8 In the graphics window select the boundaries of the hole in the first cross section Cross Section 1 otto of cylinder 9 For each successive cross section repeat the following steps e Select Next cross section on the property sheet menu f In the graphics window select the boundaries of the next cross section g Select Hole on the property sheet menu h In the graphics window select the boundaries of the hole in the identified cross section Cross Section 2 Physical Properties User Guide and Menu Reference 4 19 Calculating Mass Properties Calculating Mass Properties Using Cross Sections The steps are repeated for the third cross section Cross Section amp The steps are repeated for the fourth cross section d Cross Section 4 The steps are repeated for the fifth cross section de Cross Section 5 4 20 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating Mass Properties Using Cross Sections The steps are repeated for the last cross section h 7 4 diz dzs ds da da Cross Section 6 Top of cylinder 10 When finished select Do
77. rom the Query menu 3 When the property sheet appears select the options and enter any necessary information Units wy Current model units Centimeter gram second cond Meter kilogram second Thickness 0 00000000000000 Apply Physical Properties User Guide and Menu Reference 1 17 Getting Started Extracting Parametric Mass Properties Data The options are Option Description Units Specifies the type of units to calculate the mass properties The default option is to perform the calculations using the current model units Density Specifies the density of the surface or solid you select default 1 00000000000000 Enter a density value from the calculator Thickness Specifies the thickness of the surface you select the default is 0 00000000000000 Enter a thickness value from the calculator 4 Select Apply The following menu appears on the property sheet If you select more than one object you can optionally specify the density and thickness separately for each from the property sheet menu 5 In the graphics window select one or more solids and or surfaces 6 Select GO 1 18 Physical Properties User Guide and Menu Reference Getting Started Extracting Parametric Mass Properties Data 7 The results of the calculations are displayed in the Report window Physical Properties Report Type Entity Name Density Thickness 1 Solid No
78. roperties User Guide and Menu Reference 5 25 Working with Mass Points Highlighting Mass Point Associations Highlighting Mass Point Associations The Highlight function enables you to highlight the mass points and or solid Tsurf associated to the selected mass point The highlight colors are listed below e Red for solid Tsurf and source mass point e Green for merged mass points e Blue for the first source mass point of the MERGE MPOINT SUBTRACT operations You can optionally move the marked entities onto a specified layer The two Highlight menu options obtained from the Physical Properties submenu are shown below The first enables you to simply highlight the entities associated to the selected entity The second moves the highlit entities to a specifies layer When you use either option you are prompted to select one mass point or one parametric or explicit solid Tsurf or mass point A report is issued to the CADDS dialog window indicating pertinent information based on the selected entity See online command help for the MARK MPOINT command for more detail 5 26 Physical Properties User Guide and Menu Reference Working with Mass Points Breaking Mass Point Associativity Breaking Mass Point Associativity The Dissociate function enables you to break an associative mass point relationship You can break an association by either selecting a solid Tsurf it s associated mass point or a merged mass point
79. ross section consists of a curve or series of curves that enclose one or more regions within a plane A cross section also can consist of a single point Accuracy of the Cut and Sum Method The number of cross sections used in the calculation determines the accuracy in the cut and sum method Errors due to interpolating between the given cross sections could result in large deviations form the theoretical physical properties Physical Properties User Guide and Menu Reference 1 7 Getting Started Overview of Physical Properties Functions Top view Exercise care to interpret the results obtained by the cut and sum method Appendix B describes techniques helpful when determining which object and appropriate calculation method you should use Requirements 1 The planes of all cross sections must be parallel 2 Boundary curves in each cross section must lie in the same plane 3 The distance between cross sections need not be fixed that is variable thickness is allowed between cross sections Please note An example KA R ay os a 4 i af Front view Liomedtic wew z 1 8 Physical Properties User Guide and Menu Reference Getting Started Using Physical Properties Using Physical Properties This section explains how to calculate area volume and mass properties how to work with mass points and how to report mass point data in the Explicit environment Preliminary Procedures
80. square s four line boundaries in order 6 Select More boundaries from the property sheet menu 2 5 Physical Properties User Guide and Menu Reference Calculating Areas Calculating Combined Areas 7 Select the circle CA0DS Graphics Window cls d a 8 Select Done from the property sheet menu The system reports the results in the text window AREA 53 2743339 2 6 Physical Properties User Guide and Menu Reference Calculating Areas Calculating an Area with Holes Calculating an Area with Holes The following example calculates the area of a square with two holes 1 Select the Physical Properties icon from the Model Taskset on the side bar 2 Select the Calculate Area icon from the menu 3 When the property sheet appears select the Calculate Bounded Area icon 4 Select the options you want and enter the necessary information In the example the chosen option is to subtract the area of hole s Calculate Are ss point 6 In the graphics window select the square s four line boundaries in order The example uses the Chain selection aid from the top bar and selects one of the lines 7 Select hole from the property sheet menu 8 Identify one of the holes 9 Select More holes from the property sheet menu Physical Properties User Guide and Menu Reference 2 7 Calculating Areas Calculating an Area with Holes 10 Identify the other hole A003 Graphics
81. ss Points Reporting Mass Point Data 3 When the property sheet appears select the Axis option Polar ATS Principal axes eee E inh hn aE D DE O E se Apply 4 Select Apply The following menu appears under the property sheet Define Axis Done 5 In response to the MODEL ent prompt in the command line select the mass point 6 Select Define axis from the property sheet menu 7 In response to the MODEL loc prompt in the command line select two locations to define an axis about which the system will output the moment of inertia and radius of gyration Physical Properties User Guide and Menu Reference 5 9 Working with Mass Points Reporting Mass Point Data In the example the End constraint is used to select the two end points of the line to define the axis 8 Select Done from the Property sheet menu The system displays the mass point information in the text window VALUES ARE GIVEN WITH RESPECT TO MODEL SPACE COORDINATES Tag no tag selected VOLUME 23 13274 MASS 23 13274 CENTROID KX 0 0 Y 1 0 Z 0 0 FIRST MOMENTS MYZ 0 0 MXZ 23 132741 MXY 0 0 MOMENTS OF NERTIA IXX 55 80973 IYY 49 932149 IZZ 55 80973 PRODUCTS OF NERTIA IXY 0 0 IXZ 0 0 IYZ 0 0 MOMENT OF NERTIA ABOUT SELECTED AXIS 142 463114 RADIUS OF GYRATION 2 4
82. system responses in the CADDS text window or on any command line Variable in user input tar cvf dev rst0O filename Replace the variable with an appropriate substitute for example replace filename with an actual file name Variable in text tagname Indicates a variable that requires an appropriate substitute when used in a real operation for example replace tagname with an actual tag name CADDS commands and INSERT LINE TANTO Shows CADDS commands and modifiers as modifiers they appear in the command line interface Text string SRFGROUPA or SRFGROUPA Shows text strings You must enclose text string with single or double quotation marks Integer n Supply an integer for the n Real number X Supply a real number for the x mkdir cdrom Indicates the root superuser prompt on command lines rlogin remote_system_name Indicates the C shell prompt on command lines 1 root rlogin remote_system_name 1 Indicates the Bourne shell prompt on command root lines Window Managers and the User Interface According to the window manager that you use the look and feel of the user interface in CADDS can change Refer to the following table Look and Feel of User Interface Elements User Interface Element Common Desktop Environment CDE on Solaris and HP Window Manager Other Than CDE on Solaris HP and Windows Option button ON Round filled
83. t When you select the Change option the following options appear Mass Points Volume Urt areas _ Unit Lb Z in3 lensity Change PEN Tz Iyz You can change the values for any of the following options e Area e Mass e Ixx x moment of inertia e Ixy xy product of inertia 5 22 Physical Properties User Guide and Menu Reference Working with Mass Points Changing Mass Point Data e lyy y moment of inertia e Volume e Surf area e Ixz xz moment of inertia e lyz yz product of inertia e Izz z moment of inertia You can also change the coordinate system that the mass property values reference by selecting a Cplane from the list of existing Cplanes that appears You can use the Description option to access the DESCR property attached to the mass point You can use this property to store material identifiers and other user specified data within the mass point For more information about creating CADDS properties attributes attached to entities see the INSERT PROPERTY command in online command help After selecting the mass properties you want to change and entering the new values select Apply Then identify the mass point whose properties you want changed Changing Associative Mass Points The only aspects of an associative mass point that can be changed by the CHANGE MPOINT command are density and description When you attempt to change any other aspect of the associative mass point the
84. t htmldoc mainmenu html UNIX CDROM_Drive htmldoc mainmenu htm1 Windows Physical Properties User Guide and Menu Reference ix Preface Online Command Help You can view the online command help directly from the CADDS desktop in the following ways e From the Information Access button on the CADDS desktop or the LDM e From the command line From the Information Access Button on the CADDS Desktop or LDM 1 Start CADDS 2 Choose Information Access the i button in the top left corner of the CADDS desktop or the LDM 3 Choose COMMAND HELP The Command Help property sheet opens displaying a list of verb noun combinations of commands From the Command Line Type the exclamation mark to display online documentation before typing the verb noun combination as follows 01 INSERT LINE Printing Documentation A PDF Portable Document Format file is included on the CD ROM for each online book See the first page of each online book for the document number referenced in the PDF file name Check with your system administrator if you need more information You must have Acrobat Reader installed to view and print PDF files The default documentation directories are e usr apl cadds data html pdf doc_number pdaf UNIX e CDROM_Drive usr apl cadds data html1 pdf doc_number pdf Windows Resources and Services For resources and services to help you with PTC Parametric Technology Corporation
85. te Associative mass points can be created only if the solid or Tsurf to which they pertain is physically located within the active part Parametric Environment Within the Parametric environment you can use the Calculate Properties option to report the following properties of the surfaces or solid you select e Volume e Surface area e Mass e Centroid Center of Mass e First mass moment e Moments of inertia e Principal moments of inertia e Principal axes Please note Except for information on extracting data Extracting Parametric Mass Properties Data the remainder of this book explains procedures for calculating and displaying physical properties data within the Explicit environment Object Types Physical properties can be calculated for four types of objects two dimensional implied surface of revolution implied tabulated cylinders and objects defined by cross sections You can calculate physical properties for the following types of objects e Two dimensional planar region bounded by a series of curves e Implied surface of revolution consisting of one or more bounded regions within a plane and an axis of revolution Physical Properties User Guide and Menu Reference Getting Started Overview of Physical Properties Functions e Implied tabulated cylinder consisting of one or more bounded regions within a plane and an axis of projection Additionally you can represent the object as a series of cross s
86. the number the more accurate the results The default is 2 The following options are available with any method except as noted General Option Mass point Holes Surface area Description Creates in Model mode only a mass point symbol at the centroid center of mass of the given boundaries to store the results of the calculations See Calculating Mass Properties Using a Solid and Associativity for an example Specifies one or more hole boundaries the negative area to subtract from the defined bounded area the positive area The total negative hole area is subtracted from the total positive area to calculate the resulting area This option is not available with solids or volume enclosed by surfaces Calculates the outermost surface area of the object When using the rotation or projection method it is the surface area generated by the first boundary selected for the cross sections method it is the area of a surface interpolated between the first boundaries of each section This option is not available with solids Physical Properties User Guide and Menu Reference 4 7 Calculating Mass Properties General Mass Properties Calculation Procedures Associative This option creates an associative relationship between the selected Solid or Tsurface and the resultant mass point entity Note The solid or Tsurf must be physically located within the active part for the association to be created
87. the volume defined by the rotation of an object s boundaries about an axis The axis for rotation must lie in the plane of the boundaries All of the boundaries must be on the same plane and no boundary can intersect itself 3 4 Physical Properties User Guide and Menu Reference Calculating Volumes General Volume Calculation Procedures If you select the rotation method to calculate volume the following options are available Option Description Start Angle Specifies the minimum extent of the angle of rotation default 0 which is measured from the plane of the boundaries according to the right hand rule End Angle Specifies the maximum extent of the angle of rotation default 360 which is measured from the plane of the boundaries according to the right hand rule Calculates the volume defined by a series of cross sections If you select the cross sections method to calculate volume the following options are available Option Description Sections Specifies the number of cross sections defining the object default 2 Start layer Specifies the layer on which the first cross section is identified default layer 1 Increment layer by Specifies the increment in the layer number of successive cross sections default 1 Please note The cross sections method for calculating volumes is approximate because the variation of the shape of the part between cross sections is not known Th
88. u enough information to find the moments of the object because the shape of the object between S1 and S2 is not defined Physical Properties User Guide and Menu Reference C 1 Cross Sections Method Calculations Therefore you must use an appropriate formula to find the moments of the object from the available information In finding the volume and first moments of the object you can assume that the area between S1 and S2 changes with the height like a cone as follows In this formula r is a fictitious radius and the ks are arbitrary constants The above assumptions are exact for cones pyramids and other objects for which the square root of the cross sectional area is proportional to the height H From these assumptions the volume enclosed by two cross sections is calculated as follows Vol H 3 fAl AlAZ AB The first moments are given by F YVolCM1l H 12 Al 342 ZALAZ CMECHIL where Al A2 are the areas of S1 and S2 and CM1 CM2 are the locations of the centroids of S1 and S2 C 2 Physical Properties User Guide and Menu Reference Cross Sections Method Calculations No similar formula exists for the second moments which are therefore found by averaging the second moments of the projections of S1 and S2 along the vector joining CM1 and CM2 as follows 2 Ixx H 2 p i i AB 3 F A FIXE Ilex oe 2 Iyy H 2 f Al AZ 3 Fly F2y Y Ilyy see ITze HS fAl
89. uide and Menu Reference Calculating Volumes General Volume Calculation Procedures 2 Select the Calculate Volume icon from the Physical Properties command palette to display the following property sheet Calculate Volume Mass point aA End depth 1 0000 Apply The following options are available for calculating volume Option Description Calculates the volume defined by the projection of an object s boundaries along an axis The axis for projection must notlie in the plane of the boundaries All of the boundaries must be on the same plane and no boundary can intersect itself Physical Properties User Guide and Menu Reference 3 3 Calculating Volumes General Volume Calculation Procedures If you select the projection method to calculate volume the following options are available Option Description Start depth 0 0000 Specifies the distance from the plane of the boundaries to the bottom low boundary of the projected object default is 0 0 measured along the axis from the plane of the boundaries End dept 1 0000 Specifies the distance from the plane of the boundaries to the top high boundary of the projected object default is 1 0 measured along the axis from the plane of the boundaries Projection axis 4 r i 5 A Expected solid High i r after projection boundary K 4 End depth y Closed boundary Low boundary Start depth Description Calculates
90. ulating Mass Properties Calculating the Mass Properties of a Projected Object 9 In the graphics window select the square s four lines in order Projection ans 10 Select Done from the property sheet menu The system calculates the mass properties surface area and center or mass position centroid It creates a mass point and reports the results in the text window Mass point VOLUME 23 13274 MASS 23 13274 CENTROID X 0 0 Y 1 0 Z 0 0 FIRST MOMENTS MYZ 0 0 MXZ 23 132741 MXY 0 0 MOMENTS OF INERTIA IXX 55 80973 IYY 49 932149 IZZ 55 80973 PRODUCTS OF INERTIA IXY 0 0 IXZ 0 0 IYZ 0 0 4 12 Physical Properties User Guide and Menu Reference Calculating Mass Properties Calculating the Mass Properties of a Rotated Object Calculating the Mass Properties of a Rotated Object To calculate the mass properties of a hemisphere with a cylindrical hole in the base using the rotation calculation method Cylindrical hole 1 radius and 1 high 1 Select the Physical Properties icon from the Model task set on the side bar 2 Select the Calculate Mass Properties icon from the menu n When the property sheet appears select the Rotation Method icon 4 Select the options you want and enter the necessary information Physical Properties User Guide and Menu Reference 4 13 Calculating Mass
91. use either the projection or rotation methods whenever possible Specify as many cuts as possible near the region of the part where extreme changes of geometry take place if the cross sections method must be used See Appendix B for more details on the cross sections method Physical Properties User Guide and Menu Reference 4 5 Calculating Mass Properties General Mass Properties Calculation Procedures Using a Solid This option enables you to calculate the mass properties of a solid See Using a Trimmed Surface to learn about the available options Using a Volume Enclosed By One or More Surface This option enables you to calculate the mass properties of a volume enclosed by one or more surfaces You can apply a scale factor to the display of the object s surface normals The default normal length is 3 0000 If surfaces overlap or intersect one another CADDS does not check the object s validity and results of the calculations may be incorrect Using a Trimmed Surface This option enables you to calculate the mass properties of a trimmed surface Tsurf Selecting the Trimmed Surface option allows you to select a trimmed surface or solid If a solid is selected the mass properties are calculated as if the surface of the solid is a thin shell This option also allows you to specify thickness and accuracy e Thickness When you specify thickness the density is the mass per unit of volume The thickness you
92. ust be lined up and left justified under the corresponding keyword Do not use tabs The table must be sorted alphabetically by IDENTIFIER Physical Properties User Guide and Menu Reference 6 5 Calculating Center of Gravity Calculating Center of Gravity Output Report Filename This is the name of the text file that receives the report produced by Calculate Center of Gravity The default name is CG OUTPUT Output Report Weight Units This specifies the type of weight units used in reporting results Calculate Center of Gravity converts the units in the mass table to the units you specify here The default is the unit specified in the mass table Possible units are listed below Abbreviation Unit LB Pounds KG Kilograms LTONS Long tons 2240 pounds STONS Short tons 2000 pounds MTONS Metric tons OZ Ounces GM Grams Properties Selecting Include Property Value in Output Report allows you to specify properties whose values are used as identifiers in the mass table You can specify up to ten property names The system looks for the specified property on all entities selected It obtains the value of the property and uses that value as an identifier to match against identifiers in the mass table When specifying properties follow the rules below e Real valued identifiers must contain a period e Negative numeric values are not allowed Mass Points Selecting Create Mass Point for
93. wn in the Figure B 3 The object is defined by a ruled surface between two ellipses on parallel planes 10 units apart with their major axes perpendicular to each other The ellipse with its center at XOYOZO has a half major axis of 5 and a half minor axis of 2 The ellipse with its center at XOYOZ10 has a half major axis of 5 and a half minor axis of 1 5 The object is cut with a plane perpendicular to the z axis into different numbers of sections Mass property calculations are performed on the cuts Figure B 3 A Ruled Surface between Two Ellipses Top view Front wiew Ioometic Weve z The Figure B 4 is a graph of the calculated volume versus the number of cuts used It shows that for this geometry increased accuracy is achieved as the number of cuts is increased to about 20 beyond which more cuts do not improve the answer significantly Physical Properties User Guide and Menu Reference B 5 Improving Mass Properties and Volume Calculations The Cross Sections Method Figure B 4 Calculated Volume Plotted Against the Number of Cuts Humber of steps Number of sections 1 TO OU Thickness of each section Humber of sections A useful technique for extrapolating the correct answer is to plot this data versus the reciprocal of the number of cuts as shown in the Figure B 5 You can see that the volume of the object is between 269 and 270 B 6 Physical Properties User Guide and Menu Reference Improving Mass Propert
94. you have the following options e Type of units for calculation output Choose among the following unit types e Current model display units the default e Centimeter gram second CGS e Inch lb mass second ENG e Meter kilogram second MKS e Density for the solid or surface A density value is needed to calculate the properties the default is 1 0000 e Thickness of the surface A thickness value is needed to calculate the properties of a surface If you do not specify a thickness the default value used is 0 0 therefore only surface properties are calculated You can select more than one surface or solid in which case a single report is displayed with the total mass properties of all your selections Please note Mass property calculations are only valid for the current state of the model Therefore recalculate the mass properties for any model you regenerate 1 16 Physical Properties User Guide and Menu Reference Getting Started Extracting Parametric Mass Properties Data Restrictions Note the following restrictions e Mass property calculations have a tolerance of 1 10 of 1 percent e Mass property calculations in the Parametric environment do not retain the calculation data in the model database or create a mass point as is the case in the Explicit environment Calculating Mass Properties To calculate mass properties KA 1 Select the Query icon from the top bar 2 Select the Mass Properties option f

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