Inheritance features are a major enhancement to merge geometry features. They also provide many of the benefits of family tables without the overhead and data management drawbacks. This functionality is enabled by the Advanced Assembly (AAX).
These data sharing features provide a one-way associative propagation of geometry and feature information to derivative parts (slave). They enable visibility into the model tree for the base model (master), and are fully functional, even when the reference part is not in session. In fact, there is an option to toggle the dependency (enabled by default). Because of the one-way associativity, “revision bumping” is prevented on the source model, while retaining the flexibility necessary for downstream/variant functions.
An inheritance feature begins with all of its geometry and data identical to the reference part from which it is derived. You can then define the following varied items:
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Dimension and Tolerance values
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Suppress or Resume features
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Annotations (including geometric tolerances and symbols)
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Parameters
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References
Typical use cases for this powerful data sharing feature are:
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As-Cast/As-Machined models
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Analysis/Simulation models
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In-process models to show manufacturing evolution
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Design variants (without family tables)
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Hide IP from suppliers (combined with family tables)
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Model localization for stock material availability
Multiple inheritance features can be created in the same model and can even be nested. In many cases, they are a good alternative to external copy geometry. One advantage to this approach is access to feature information directly and via relations.
Creating an Inheritance Feature
An inheritance feature can be created in the context of an assembly, or in part mode as external. The benefit of creating as external is that no dependency is established to an assembly for relative placement. The dashboard allows converting from one type to another. Pro/ENGINEER Wildfire 3.0 even allows toggling between merge and inheritance, but be aware that varied items will be lost.
Figure 2 shows the dashboard that will appear.
- Select or Open a reference model
- Place the reference model using assembly constraints
- By default, a MERGE feature will be created. Select
to Toggle Inheritance
If you are working in the context of an activated part in an assembly, the reference type will be “Assembly context”, but it can be toggled to “External.” (Figure 3)
Dashboard Options
- References for annotations and Copy Datums are only available for Merge, but Annotation Features are included by default in Inheritance
- Refit Datums and Varied Items are only available for inheritance
- Note that Dependent status can be enabled/disabled
Define Variations
This is similar to the functionality you may be familiar with from defining a family table. This captures the variations that are applied against the master model during regeneration. The tabs are self-explanatory.
- Select Options > Varied Items (Figure 4)
- Use the fields and drop-down menus to specify “New” values or states
Resulting Feature and Model Tree (Figure 5)
- After completing the feature, notice that an expandable node appears in the Model Tree. The context menu (RMB) can be used to easily Open Base model, Edit Definition, or Update Inheritance, etc
- If features under the inheritance structure are directly modified, suppressed, and so forth, in this context they will automatically be added to the Varied Items table shown in the previous section.
Accessing Relations and Parameters
Use the following syntax to access the inherited parameters and dimension symbols of the base model:
symbolic_name:IID_#
symbolic_name is the dimension symbol or parameter name
# is the internal ID of the inheritance feature
Local parameters of the inheritance feature are accessed using:
param_name:FID_#
# is the feature ID of the inheritance feature
These can be combined to access the feature parameters of the inherited feature:
param_name:FID_#:IID_#
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