Copy geometry features are a good way to propagate design intent between Pro/ENGINEER models. Curves, edges, surfaces, and datum features can be included in a copy geometry feature. The problem comes when a copy geometry feature will not regenerate. This is likely to mean that critical information is not being updated in one or more components of a design. Outlined below are some recovery techniques for resolving these failures.

Determining Unknown External References

If you have ever had to work with a model that contains a copy geometry feature that you did not create, you have probably pondered not only the existence of that feature but also what intent it should convey. Using the following procedure, you will be able to identify the external references of a given copy geometry feature, which should also provide some insight into the design intent.

The Global Reference Viewer is often useful when troubleshooting (see sidebar). The problem is that the parent object of the copy geometry is not in session and of unknown origin. To identify and locate the unknown references, follow these steps.

1. Open the part of interest. Retrieve the model that contains the copy geometry feature.
2. Pick info/global_ref_viewer (Global Reference Viewer). Use Info, Global Ref Viewer to launch the viewer (Fig.1).
3. Set the Global Reference Viewer filter to Feature, External, and Objects with Parents (default set-tings). Left-click on the filter settings in the Global Reference Viewer window and check that the settings are correct.
4. Double-click on the part of interest in the Main Tree (Fig. 2).
5. Double-click on the parent object in the Main Tree. Confirm to switch context to parent object by clicking on the Yes button.
6. Confirm to retrieve object not in session. If the parent object is not currently in session, you will be prompt-ed to confirm the retrieval of the parent object. Click on the Yes button to con-firm retrieval (Fig. 3).
7. Double-click on the part in the Main Tree again. You should see the parent and child references window update with information in the panes. The parent and child references window now shows the structure of the parent object(s) and references within the parent(s) that are passed through the copy geometry feature. You can now see what external references the copy geometry feature affects (Fig. 4).
8. Select Full Path from the action menu in the Global Reference Viewer. Using the left mouse button, select Action, Full Path. This displays all external references in an information window. You can now investigate the nature of all external feature references related to this copy geometry feature, as well as the dependency chain through which the references are passed.

Rerouting References of a Failed Copy Geometry Feature

What happens if the external references of a copy geometry feature are lost or corrupted? You will see an error message that Pro/ENGINEER cannot find the references of the feature. In many cases, you can overcome this problem with less work than if you have to recreate the model from scratch. This recovery strategy does require, however, that you have access to the assemblies where the external references were originally created.

1. Retrieve into session the highest-level assembly that the copy geometry feature references. Using the technique described previously, you can find out which assembly is relevant to this step. If the copy geometry fails during regeneration, erase the part from session (File, Erase, Current). Then retrieve the part and proceed to the next step.
2. Redefine the failed copy geometry feature to be independent (Feature, Redefine, Dependency, Independent, Done, OK). Then retrieve the highest-level assembly referenced into session. This will allow you to see the features referenced by the copy geometry feature so that you can recreate a functional equivalent. Using the highest-level assembly ensures that all of the children of the copy geometry feature are visible.
3. Create a new copy geometry feature identical to the failed copy geometry feature. This may present a problem if you do not know what the failed copy geometry feature was meant to accomplish. Use the Global Reference Viewer to identify the missing references. If the features used were named, you can probably identify what the references were.
4. Reorder the new copy geometry feature before the failed copy geometry. By doing so, you can reroute all of the children of the failed copy geometry and delete the failed copy geometry feature.
5. Reroute the children of the failed (old) copy geometry feature (Feature, References, All Children) to the new copy geometry feature.
6. Suppress the failed copy geometry feature and regenerate. Fix all features that fail as a result of this suppression.
7. Delete the old copy geometry feature and save the model. You have now successfully established a new copy geometry feature that allows design intent to be shared.

Thomas Braxton is an engineering section manager at Motorola BCDC in Boynton Beach, Florida, USA. He can be reached by email at thomas.braxton@motorola.com.