Export to step file

Hi there!

When I export closed polysurfaces (solids) as a step file and re-import them they tend to become open polysurfaces. I‘ve had this issue before and so far I could not find a solution. I tried all the options already but that does not seem to make a difference.

The geometry is usually very complex and has several thousand surfaces.

I use this way to create geometry for a customer using inventor. Sometimes they can ‚repair‘ the geometry, sometimes they can‘t.

I couldn’t find any more clues in the internet so I was hoping someone here has any ideas.

Thanks a lot!

This can happen if the tolerances differ between Rhino and the app that opens the Step. Are you using Rhino for both the Step creation and the Import though? Can you provide a sample 3dm and resulting Step either way?

Another thing that can cause this is edge tolerances. Run the What command on one of the surfaces that goes wrong before exporting as Step. If the range for the Edge Tolerance section is large like 0.00 to 0.1 that could also be the issue. You can use RebuildEdges in Rhino to fix it but this can lead to a gap requiring further work.

Post even a small portion of one of these models that shows the issue if none of this helps.

Hi Brian, thanks for your fast response!

Ok it seems after rebuilding the edges I have plenty of naked edges. Is there a way to easily fix this?

Guess I have to rebuild many surfaces manually though. Tolerance seemed to be the main problem.

So if similar problems occur I’ll post a model.

No easy fix for surfaces that weren’t modeled accurately within the needed tolerance after the fact.
Edit your way through the file to add the accuracy AND precision your down process systems require.