About Fixed Geometry Settings
You can define an edge as the default fixed geometry reference for unbend and bend back operations in the board part. Keep in mind the following points:
The first segment is automatically defined as the fixed geometry reference, if it is a valid reference.
Best practice is to select the same fixed geometry reference for all unbend and bend back features.
All part instances use the selected fixed geometry reference of the generic model.
The fixed geometry reference that you define for a part is used as the default reference for unbend and bend back features. However, you can set a different feature-specific fixed geometry reference as needed.
If no fixed geometry reference is defined for a part:
The fixed geometry reference selected for the first unbend or bend back feature is automatically used as the part fixed geometry reference.
The part fixed geometry reference does not update when the feature-specific reference is redefined.