ITEM Tutorial
Step 4: Connect Volumes
The next step in the mesh generation process is to merge all shared curves and surfaces. This is necessary so that adjacent volumes can shared boundary meshes. For most geometries, this step presents no major complications. But in many cases, misalignments, tolerance problems, or other cleanup operations can prevent proper merging. The ITEM panel is designed to guide users through imprint/merge problems.
- Click Connect Volumes
- Click Imprint and merge
- Click on the button with three small dots (...) next to the Merge Tolerance field
- Click Estimate Merge Tolerance. The merge tolerance panel is used to help the user find an appropriate merge tolerance. In addition to determining a proper tolerance for merging, the merge tolerance can also be used as a diagnostic tool to find small misalignments, as will be demonstrated below. Many of these can be resolved prior to imprinting and merging.
- Check vertex-curve and vertex-surface pairs
- Look in the ouput of the command line workspace. A proximity is nearly coincident entities that would be merged at the given tolerance. From the given list, you can tell that there are 4 entities that would be merged at a merge tolerance of 0.025 which would not be merged if the merge tolerance were 0. This means that those entities are less than 0.025 apart.
- Change the search parameter to very small number like Min=0.001 and search again.
- Four Vertex-Vertex Pairs appear
- Open Vertex/Vertex pairs group
- Right click on first pair and choose Label Pair to view
- Click on the first solution (tweak surface 46 to surface 7) and click Execute
- Click Done
- Click Imprint/Merge button
- Click Detect Potential Problems
- .
No problems should appear on the list, signifying that imprinting and merging has most likely been successful. There are several diagnostic tools on this page that help to determine if imprint/merging has been successful. These include:
- Overlapping Surfaces- Surfaces that overlap, but are not merged.
- Non-manifold curves- Two curves that are merged but that don't have any merged surfaces.
- Non-manifold vertices- Two vertices that are merged, but do not share any merged curves.
- Floating volumes- Volumes that are not connected to any other volumes (meaning they are not merged)
All of these diagnostics could be run at any time but the results are most meaningful after an imprint/merge operation.
