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Vertex/edge/face IDs

tony_459tony_459 Member Posts: 206 ✭✭✭
I export part geometries (as STEP files) for use in 3D multibody simulations. I often add new connections to parts before simulation---to apply forces, add pulley or gear constraints, maybe sense motion---and these are ultimately based on the IDs of vertices, edges, or faces that I select from the STEP file geometries I export.

Trouble is, when I modify a part in Onshape and export to replace the original in my simulation environment, the IDs change, and my part connections then move elsewhere on the part or disappear altogether (if the original IDs no longer exist).

Most of the time, the change in geometry is something little---adding or removing a fillet, chamfer, or hole, say, or tweaking proportions. It seems the IDs of unchanged vertices, edges, and faces should stay the same---and, now that I think of it, so should the IDs of edges and faces that maybe are a little bigger or have slightly different proportions *but* still exist, even if in a different form.

Is there a way to keep IDs from changing---some best practices I'm not aware maybe? Thanks! :)
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