Feature Detection is based on the principle of Feature Based Meshing. Feature Based Meshing (FBM) is a meshing set up that uses set of rules on how to treat certain geometric features while meshing. Feature Based Meshing has two parts:
Feature Recognition
Mesh Treatment
FBM performs the following on the geometry features:
Recognize the features like holes, fillets and more.
Categorize the feature based on geometric parameters or queries.
Defines mesh treatment per detected feature.
FBM allows you to minimize the operation performed at geometry level and create an automated or repeatable process to reduce the pre-processing time.
To perform the Feature Detection:
In Mesh Context tab, click Feature Detection under the Detect group to open the worksheet for feature detection.
or
Right-click Model object and click Insert > Feature Detection to open the Worksheet for feature detection.
Select the feature to be detected and provide the required options in Feature Detection Worksheet.
Right-click Feature Detection in the model tree and click Detect Features to detect the features in the worksheet.
or
Click Detect Features in the worksheet to detect the selected features.
The Named Selections for the features are created in the model tree and the feature controls are available under the mesh object.
The Details view has the following options:
Scope
Scoping Method: Allows you to select Geometry or Named Selection for scoping of the feature.
The Feature Detection Worksheet has the following options:
Name: Allows you to provide name for the feature to be detected
Type: Allows you to select the type of feature to be detected. The available types are Shell Fillet, Shell Hole, Solid Fillet, Solid Hole, Solid Concave Fillet, Solid Convex Fillet.
Criteria: Allows you define the criteria applied for the feature based on their type. The available criteria for Fillets and Holes are Radius and Variable Radius.
Operator: Allows you to specify the condition for the selected criteria. The available operators are Equal, Not Equal, Less Than, Less Than or Equal, Greater Than, Greater Than or Equal, Exclude range, Include range.
Value: Allows you to provide value for selected criteria of the feature.
Angle: Allows you to provide the angle for the selected feature.
Min Bound: Allows you to provide minimum value for the selected feature.
Max Bound: Allows you to provide maximum value for the selected feature.
Mesh Treatment: Allows you to specify the mesh treatment to be applied on the selected feature. Mesh Treatment applied varies with the type of the feature. The available mesh treatment for various features are as follows:
Shell Hole: The available mesh treatments are None, Fill Hole and Quad Layer Control. When Mesh Treatment is set to Quad Layer Control, the non-circular holes are filtered out.
Shell Fillet: The available mesh treatments are Mapped Meshing and Deviation Control. When Mesh Treatment is set to Mapped Meshing, non-mappable faces are filtered out.
Solid Hole: The available mesh treatments are None, Mapped Meshing.
Solid Fillet: The available mesh treatments are None, Mapped Meshing. When Mesh Treatment is set to Mapped Meshing, non-mappable faces are filtered out.
Solid Concave Fillet: The available mesh treatments are None, Mapped Meshing. When Mesh Treatment is set to Mapped Meshing, non-mappable faces are filtered out.
Solid Convex Fillet: The available mesh treatments are None, Mapped Meshing. When Mesh Treatment is set to Mapped Meshing, non-mappable faces are filtered out.
Solid Fillet Rib Edges: The available mesh treatments are None.
Shell Fillet Rib Edges: The available mesh treatments are None.
Add Feature Detection: Allows you to add a new row in the feature detection worksheet.
Detect Features: Allows you to detect the features with specific criteria mentioned in the worksheet.
Best Practices
The best practices to be followed while performing Feature Detection:
Feature Detection may not detect all the curved faces as fillets or holes. In such cases, you can add or remove the faces from the named selection.
In the Feature Detection worksheet, you must group the fillets or holes of the similar radius under the same Name Selections and set the Mesh Treatment. This helps you to have more control over the mesh pattern.
You should always try to provide smaller value as detection radius range. When you provide higher value or use operators such as Greater Than or Greater Than or Equal, Feature Detection may detect faces as fillets or detect the sheet boundary edges as holes.
When Mesh Treatment is set to Mapped Meshing, non-mappable faces are filtered out of the named selection group and provides a warning message.
When you apply Mapped Meshing as Mesh Treatment on large number of fillets in a complex geometry with large number of faces, performance issues may occur. This could also reduce robustness of the meshing because mesh based defeaturing is not performed on the edges of the faces with mapped mesh control (except in the case of Explicit Physics Preference Patch Conforming Tet meshing). Hence, it is recommended to limit the number of fillets selected for Feature Based Meshing specifying specific radius ranges and focusing on bodies or locations that are most important for analysis accuracy.
Feature Detection is a single operation acting on all or selected bodies. When it is re-run, the Named Selections created prior to the execution of Feature Detection are removed and new ones are created. If you want to retain the previous Named Selections, you can right-click and duplicate the Named Selections groups before executing Feature Detection again.
Limitations
Feature Detection has the following limitations:
Feature Detection detects only circular bolt holes for solid holes.
When you Pull a 2D surface with circular holes to form a 3D body, the Feature Detection may not detect the circular holes on the pulled surface.
Bodies with Virtual Topology are not considered for Feature Detection.