System information

SolveSpace version: All

Operating system: All

Expected behavior

We should be able to cut a revolved or lathed surface on the seams without failure.

Actual behavior

The surfaces in the cutting plane are missing.

Additional information

I believe this is the same root problem as #540 and #652 and the solution may impact issues #680 and #683. I've created this with a simplified test case here:
coincident4.zip
Picture: