Chapter 6 Working with CAD DesignModeler

Working with CAD Bodies and Parts Support for CAD Versions Length Units Attaching to a CAD Session Importing CAD Files Positioning Imports Import Units Exporting a Model Creating Negative Geometry Edge and Face Merge for Model Simplification Automated Option for Ease of Use Improved Cleanup and Repair of CAD 2

A. Bodies and Parts DesignModeler is primarily intended to provide geometry to an analysis environment. For this reason we need to see how DM treats various geometries. DesignModeler contains three different body types: Solid body: Body has surface area and volume Surface body: Body has surface area but no volume Line body: Body consists entirely of edges, no area, no volume By default, DM places each body into one part by itself Individual parts will always be meshed separately If bodies in separate parts share faces, the meshes on those shared faces will not be matched Multiple bodies in a single part will have matched meshes on shared faces when meshed 3

Active and Frozen Bodies By default, DM will merge new geometry with existing geometry to maintain a single body This can be controlled by working with either frozen or active bodies You can toggle between frozen and active states for using the Freeze and Unfreeze tools 4

Active and Frozen Bodies There are two body states in DM: Active: Body can be modified by normal modeling operations (cannot be sliced) Active bodies are displayed in blue in the Feature Tree View Frozen: (Tools>Freeze) Two Purposes: Provides alternate method for Assembly Modeling Provides ability to “Slice” A Frozen body is immune to all modeling operations except slicing To move all active bodies to the Frozen state, use the Freeze feature To move individual bodies from the frozen to active, select the body and use the Unfreeze feature Frozen bodies are displayed as transparent in the Tree View Active Frozen 5

…Bodies and Parts Body Suppression: Suppressed bodies are not plotted Suppressed bodies are not sent to other Workbench modules for meshing or analysis, nor are they included in the model when exporting to a Parasolid (.x_t) In the tree view an “X” is shown near suppressed bodies Unsuppressed Suppressed 6

… Bodies and Parts Parts: By default, DesignModeler places each body into one part by itself You can group bodies into parts Multi-body parts contain multiple bodies (volumes), and have shared topology. The meshes on shared faces are matched To form a new part, select two or more (or RMB “Select All”) bodies from the graphics screen and use >Tools>Form New Part The Form New Part option is available only when bodies are selected and you are not in a feature creation or feature edit state 7

… Bodies and Parts Why multi-body parts? Example: DM Mesh DM In DM: 3 parts, 3 bodies consisting of 3 solids During Meshing: 3 solids, 3 bodies Each solid meshed independently Nodes are not shared Nodes do not line-up No connection between the 3 mesh regions for fluid flow and/or heat transfer Can connect using a Grid Interface in FLUENT/CFX DM Mesh DM 8

… Bodies and Parts Example (continued): DM Mesh DM In DM: 1 part, 1 body consisting of 1 solid During Meshing: 1 solid ,1body Entire solid meshed as one entity No internal surfaces DM Mesh DM 9

… Bodies and Parts Example (continued): DM Mesh DM In DM: 1 multi-body part, 3 bodies/solids During Meshing:1 multi-body part, 3 bodies/solids Each solid meshed independently but node connectivity among solids is preserved DM Mesh DM 10

B. Support for CAD Versions Reader and Plug-In support: CAD interfaces are associative and require installation of CAD package Autodesk Inventor 2008 (Windows 32-bit) Autodesk Inventor 2009 CoCreate Modeling 2008 CoCreate Modeling - OneSpace Modeling 2007 Mechanical Desktop 2008 and 2009 Pro/Engineer WF 4 (Windows XP and Vista, 32-bit and 64-bit) Pro/Engineer WF 3 (Windows XP 32-bit and 64-bit, Windows Vista 64-bit) Solid Edge v19 and v20 SolidWorks 2008 and 2009 UG NX 5.0 and 6.0 64-bit support for all interfaces including IGES and STEP readers

…Support for CAD Versions Plug-In support: TeamCenter Engineering 2005 w/ NX5 and NX6 (Windows XP 32-bit and 64-bit) Reader support: ACIS (SAT) 19 CADNexus/CAPRI CAE Gateway CATIA V5 (R16 – R18) (Win XP 32-bit and 64-bit) CADNexus/CAPRI CAE Gateway CATIA V5 (R18 SP4+) (Win XP 32-bit, 64-bit) CATIA V4 (Windows 32-bit) CATIA V5 (R2 - R19) IGES 4.0, 5.2, 5.3 Parasolid 19.1 STEP AP203, AP214

C. Length Units When a new DM session is started a dialog box allows selection of the desired length unit (can be set as default) Units cannot be changed mid-session. 13

D. Attaching to a CAD Session If a CAD session is currently open, this automatically imports the model into the DesignModeler session File>Attach to Active CAD File Maintains Bi-Directional associativity 14

… Attaching to a CAD Session Bidirectional Refresh Refresh the geometry using parameter values from either the source CAD package or from the CAD parameters in DesignModeler's Details View. Controls the parameter name suffix allowed from CAD Package to WB.To allow all parameters (dimensions ) created inside the CAD package to come inside DM, remove DS in the Parameter Key location 15

E. Importing CAD Files File>Import External Geometry File… Cut The “active” plane in DM controls placement for “assembly” modeling (multi-bodies). Import type details: Add, Cut, Slice, etc… Does not maintain associativity Cut 16

F. Positioning Imports Both Import and Attach have a “Base Plane” property Specify the plane (orientation) in which the Import or Attach model is referenced… When creating a new Import or Attach feature, the active plane is chosen as the Base Plane by default Users select planes from the tree view or Plane pull-down list prior to import Example: XY chosen for first import YZ plane for second import Add material option chosen The Base Plane for Imports and Attaches in all agdb files prior to this upgrade is XYPLANE 17

G. Import Units Set the desired length unit when DM starts Some import types allow you to set the units via the import details (Prior to Generate) DM then converts the model length units into the current unit system 18

H. Exporting a Model File>Export … IGES exporting: When exporting the model to an IGES file, you have the option to export solids or just trimmed surfaces. >Tools>Options 19

I. Creating Negative Geometry In many cases, when you import a CAD file, it is a model for a solid part You may be interested in the fluid region surrounding or enclosed by a solid part You can by “taking the negative” of the solid part, construct the corresponding fluid region You can construct the negative of a CAD model: In the original CAD package In DesignModeler, using enclosures, fills, and Boolean body operations such as cut and slice 20

… Creating Negative Geometry Enclosure: Creates surrounding region around bodies to facilitate simulation of field regions CFD, EMAG, etc Box, sphere, cylinder or user defined shapes can be employed Cushion property allows the boundary extent to be specified (must be > 0) Apply enclosure to all bodies or only selected targets Merge property allows for automatic multi-body part creation Ensures original part and enclosure will have nodal match up when meshed

… Creating Negative Geometry Example: Circuit board model Cutaway view of enclosure Enclosure created using box option

… Creating Negative Geometry Fill: Creates frozen bodies that fill interior voids such as holes Works with active or frozen bodies Works only with solid bodies Useful in CFD applications for creating flow volumes Two Methods for Fill operation By Cavity By Caps

… Creating Negative Geometry Example: Fill by Cavity Goal is to model the interior (fluid region) of the valve block shown here The desired (37) interior faces are selected then the Fill is inserted by clicking Generate

… Creating Negative Geometry Example Fill by Cavity (cont.): Resulting fill is a frozen (meshable) body Interior region, now isolated, can be taken to the Mesher for meshing

… Creating Negative Geometry Example: Fill by Caps Goal is to model the interior (fluid region) of the hollow pipe shown here Steps: Create surfaces and close both ends of the pipe. Use > Concept > Surfaces from Edges to create the end surfaces Use Fill by Caps to create the interior flow region

… Creating Negative Geometry Example Fill by Caps (cont.): 2 1 Closed End surface 3

… Creating Negative Geometry Example Fill by Caps (cont.): 2 1 Interior Fluid Body Created

J. Edge and Face Merge for Model Simplification Merge edges and faces based on angle criteria to simplify the model

K. Automated Option for Ease of Use RMB Clusters are displayed for preview Option to edit clusters before merge RMB

L. Improved Cleanup and Repair of CAD