The CAD Assemblies mode offers additional tools for imported CAD data in Fluent Meshing. The CAD Assemblies tree represents the CAD tree as it is presented in the CAD package in which it was created. All sub-assembly levels from the CAD are maintained on import in Fluent Meshing.
Advantages of using the CAD Assemblies tree include the following:
The CAD assemblies tree enables faster visualization which saves time in part management for large, complex models comprising multiple assemblies.
It enables re-importing or updating of selected parts or bodies using different faceting qualities and topology representations from a neutral database file.
Geometry and mesh objects can be easily created for only those assemblies, parts, or bodies that are needed for the analysis. Other assemblies, parts, or bodies can be simply suppressed.
The geometry and mesh objects are linked to the corresponding CAD objects (which are then locked), enabling quick design changes and updates.
Labels can be assigned to entities, and these are preserved throughout the object-based meshing workflow in Fluent Meshing.
The use of CAD assemblies for CAD import in Fluent Meshing is described in the following sections.
The CAD Assemblies tree is created when the Create CAD Assemblies option is selected for CAD import. It represents the CAD tree as it is presented in the CAD package in which it was created. All sub-assembly levels from the CAD are maintained on import in Fluent Meshing.
To create the CAD Assemblies tree on import, enable Create CAD Assemblies in the Object Creation group box in the CAD Options dialog box. The CAD object and zone granularity can be specified in the Object Creation group box. You can choose to create one CAD object per part, body, CAD file or selection imported. Similarly, you can choose to create one CAD zone per body, face, or object imported.
Tip: Importing CAD objects by body gives an ideal CAD assemblies tree, with the original sub-assemblies preserved.
The CAD assemblies tree includes individual CAD assemblies or sub-assemblies imported in Fluent Meshing. The entity at the highest level is also referred to as the root node.
The CAD entities in the tree are categorized as components and bodies. Components represent an assembly, sub-assembly, or part in the original CAD package, while bodies are the basic entities in the CAD assemblies tree which include CAD zones. You can also set up labels for the CAD zones, if required. Named Selections are also imported as labels. These labels are preserved throughout the object-based meshing workflow in Fluent Meshing.
In addition to the context-sensitive menus, you can manage the CAD entities using hotkeys or onscreen tool buttons. Tools exist for visualizing the CAD entities, for operations such as updating and modifying the CAD entities, creating and/or modifying geometry or mesh objects, and tree selection options. See Appendix C: Shortcut Keys for more information.
Note: When working with CAD Assemblies, certain meshing ribbon tools are disabled.
At the global CAD Assemblies level, you can use the menu options to draw or delete all the assemblies imported, and obtain the locations of the referenced FMDB files. The Tree sub-menu contains options for navigation and selections in the tree.
The FMDB file (*.fmdb) is a CAD neutral file that is created when the CAD Assemblies are created during CAD import. This file enables quick re-import of the CAD data with changes to the faceting qualities and/or topology representations.
When importing a single file, the FMDB file is created in the folder containing the CAD file and has the same name as the file imported.
When importing multiple files, the FMDB file is created in the folder containing the CAD files and is named multiple.fmdb by default. You can specify an appropriate name in the FMDB Location dialog box when prompted.
The menu at the global CAD Assemblies level enables you to obtain a list of the referenced FMDB files. Select in the menu to open the Referenced FMDB files dialog box containing the list of FMDB files.
All CAD entities and labels in the CAD Assemblies tree are referred to by their path.
The path is used in commands in the cad-assemblies menu (see cad-assemblies/ for details).
To see the path, right-click the CAD entity in the tree and select > .
Examples of the CAD entity path:
|assembly.agdb|component_1 |
|assembly.agdb|component_1|body_1 |
|assembly.agdb|body_1|label |
The menu contains options that control the appearance of the CAD Assemblies tree. These options can be used to select or deselect the CAD objects and zones in the tree, expand or collapse the tree branches, and also delete suppressed or locked CAD objects.
At the global CAD Assemblies level:
The Selection Helper enables you to select or deselect CAD objects or labels in the tree based on the specified Name Pattern. You can choose cad-objects, leaf-cad-objects, non-leaf-cad-objects, or label in the Filter list.
The Select Next Level option selects the CAD assemblies or objects at the next lower level.
The Collapse All option collapses the tree to the level selected.
The Delete Locked/Suppressed option deletes all locked or suppressed CAD assemblies or objects.
The Restore Deleted option restores previously deleted CAD assemblies or objects.
At the component level:
The Selection Helper enables you to select CAD objects or labels in the tree based on the specified Name Pattern. You can choose leaf-cad-objects, non-leaf-cad-objects, or label in the Filter list.
The Select Next Level option selects the CAD assemblies or objects at the next lower level.
The Expand All option expands the tree to show all subsequent levels (CAD objects and labels, if applicable). Similarly, the Collapse All option collapses the tree to the level selected.
The Show Path option prints the CAD entity path in the console.
The Suppress Other option suppresses all other CAD entities at the same level.
The Select Associated Objects selects geometry/mesh objects associated with the selected component.
At the body level:
The Show Path option prints the CAD entity path in the console.
The Suppress Other option suppresses all other CAD entities at the same level.
The Select Associated Objects selects geometry/mesh objects associated with the selected body.
At the label level:
The Select All Parent option selects all the parent CAD entities in the tree.
The Show Path option prints the CAD entity path in the console.
CAD entities can be displayed using the options available for the CAD Assemblies tree:
The global menu for the CAD Assemblies contains an option to draw all the CAD assemblies imported.
The menu for individual components and bodies contains an option to draw the selected entity. You can also use the additional options in the menu to add, remove, or highlight the selected entity in the display. You can also draw the unlabeled zones for the entity selected.
The menu for labels contains an option to draw the selected label. You can also use the additional options in the menu to draw all labels and add, remove, or highlight the selected label in the display. You can also draw the overlapping zones for the label selected.
The CAD entities are displayed using a different color palette to that used for the geometry/mesh objects. The zone and object selection filters also apply to the CAD zones and objects.
Other visualization tools and shortcuts are also applicable to the CAD entities. You can use the shortcut keys or onscreen tools to select visible entities, deselect all or the last selected entity, hide/show entities. You can also use the Isolate tools to isolate selected entities in the display or limit the display to entities based on area/curvature of the selected entities.
The Update option enables reimporting the CAD entities using new parameters. Select the CAD objects in the tree and select . Alternatively, select the CAD objects in the graphics display and click 
to open the Update dialog box.
Tip: Be sure to clear the tree (using Ctrl+Y) before selecting items to update.
You can change the CAD zone granularity, if required.
Select the Tessellation option and specify the tessellation controls:
If you select the CAD Faceting option, you need to specify the Tolerance for refinement and the Max Size in the CAD Faceting Controls group box. The default value for Tolerance is
0, which implies no tessellation (faceting) refinement during import. The Max Size enables you to specify a maximum facet size for the imported model to avoid very large facets during the file import.If you select the CFD Surface Mesh option, you need to specify the minimum and maximum facet sizes (Min Size, Max Size), and the curvature normal angle to be used for refining the surface mesh based on the underlying curve and surface curvature. You can optionally use the edge proximity size function for creating the surface mesh, based on the number of cells per gap specified. You can also choose to save a size-field file based on these defined parameters (that is, Min Size, Max Size, Curvature Normal Angle, Cells Per Gap). Note that for proximity size functions, the number of cells per gap can be a real value, with a minimum of 0.1 (see Proximity for more information).
Alternatively, you can use a previously saved size-field file to create the surface mesh by enabling Use Size Field File.
You can choose to import edge zones from the CAD entities. Specify an appropriate value for Angle.
CAD management operations are available from the tree menus as well as through the graphics icons and hot-keys.
The menu contains options for creating geometry/mesh objects from the CAD entities and modifying existing objects. Select the CAD entities in the tree and then choose the appropriate menu option. Alternatively, select the CAD objects in the graphics display and select the option from the CAD Tools.
Use the Create (
) option to create a new
geometry/mesh object. The Create Object dialog box contains options
for creating a geometry or mesh object based on the tree selections. Specify the
Object Name, Object Type (geom or mesh), and
the Cell Zone Type (solid, fluid, or dead). In case of multiple
selections, you can choose to create One Object per CAD Object
Selection. You can also choose to retain the CAD zone granularity by
enabling Keep CAD Zones Granularity. Note: The CAD association will be transferred to the objects when you choose to retain the CAD zone granularity for object creation.
Use the Add to (
) option to add the selected
CAD entities to an existing object. The Add to Object dialog box
contains a list of the current objects. Select the object to be modified and click
.When CAD entities are added to an object, the zones are merged to create a single zone. If the CAD entities have labels defined:
Adding the entities to an object with no labels defined will result in the labeled zones retained as separate zones.
Adding the entities to an object with the same labels defined will result in the labels being merged, but retain the zones retained as separate zones.
Use the Replace option (
) to replace an existing
object with the selected CAD entities. The Replace Object dialog
box contains a list of the current objects. Select the object to be replaced and click
.
You can set up labels for the CAD zones, if required. Named Selections are also imported as labels. These labels are preserved throughout the object-based meshing workflow in Fluent Meshing.
You can manage labels for CAD entities using the Manage Labels
dialog box. Select the CAD zones in the display using the zone selection filter
(
) and then click
Manage Labels (
).
Use the Create/Add label option to create a new label for the CAD zones selected and click . If Remove CAD Zones from Graphics is enabled (default), the selected CAD zones will be removed from the display after the label is created.
Use the Create/Add label option to add an existing label to the CAD zones selected. Select the labels from the list and click . If Remove CAD Zones from Graphics is enabled (default), the selected CAD zones will be removed from the display after the zones are added to the label.
Use the Remove label option to remove an existing label from the CAD zones selected. Select the labels from the list and click .
The menu for labels contains options for deleting and renaming labels.
Use the Delete option to delete the selected labels.
Use the Rename option to rename the labels. Specify the name in the Rename Labels dialog box and click . In case of multiple selections, the specified name will be used, with a suitable index as suffix. For example, specifying a new label name wall will result in labels wall.1, wall.2, etc.
The menu for the CAD entities (component or body) contains options for setting the CAD entity state.
- Locked
CAD entities are locked when corresponding geometry or mesh objects are created. Locked entities cannot be modified or used for creating objects. This prevents the use of the same CAD entity in multiple objects.
To unlock an entity, use the > option.
- Suppressed
CAD entities can be suppressed if they are not required for the analysis. You can transfer only necessary entities to geometry or mesh objects for meshing using the object-based workflow and suppress the remaining entities.
To suppress an entity, use the > option. Alternatively, select the CAD objects and click
.To unsuppress an entity, use the > option.
The options in the menu at the CAD entity (component or body) level enable modifying the CAD entities. Select the CAD entities in the tree and then choose the appropriate menu option. Alternatively, select the CAD objects in the graphics display and select the option from the CAD Tools.
Use the Extract Edge Zones option (
) to extract the feature
edge zone for the selected entities. Specify the Angle in the
Extract Edge Zones dialog box and click
.Use the Rename (
) option to rename the selected
entities. Specify the name in the Rename CAD Assemblies dialog box
(or the Rename Entities dialog box) and click
. For multiple entities, the specified name will be used,
with a suitable index as suffix. For example, specifying a new name
wall will result in entities wall.1,
wall.2, etc.Use the Add Prefix option to add a prefix to the selected entities. Specify the prefix in the Prefix name dialog box and click .
The menu for geometry/mesh objects contains options for modifying the selected objects based on the associated CAD entities. You can also attach or detach the CAD entities from the objects.
Use the Update from CAD option to update the geometry/mesh objects based on changes to the associated CAD objects.
Use the Unlock CAD option to unlock the CAD objects associated with the selected geometry/mesh objects.
Use the Select CAD option to select the CAD objects associated with the selected geometry/mesh objects.
Use the Detach CAD option to detach the CAD objects associated with the selected geometry/mesh objects. All association will be removed and the geometry/mesh objects will be independent of changes to the CAD entities.
Use the Attach CAD option to attach CAD objects to the selected geometry/mesh objects. Select CAD objects to be associated with the geometry/mesh objects in the tree and click in the Attach CAD assemblies dialog box. The selected geometry/mesh objects will be associated with the CAD objects which will then be locked.
Use the Restore CAD option to restore the geometry/mesh object from the associated CAD objects.