Solvespace crash on new group rotating and new group revolve...

[dadoprom]

When you select the marked point and marked normal and hit either "New group rotating..." or "New group revolve..." as seen on the screenshot, solvespace crash.

System information

• SolveSpace version: 3.1~7d379e7f
• Operating system: xubuntu 22.04.4

Expected behavior

It should not crash.

Actual behavior

It did crash...

Additional information

This is what terminal says:

File ./src/srf/surfinter.cpp, line 103, function AddExactIntersectionCurve:
Assertion failed: !(sb->Start()).Equals(sb->Finish()).
Message: Unexpected zero-length edge.

slvs-crash.zip

[ruevs]

I'm away from a desktop for a while but this sounds like #1058 and/or #1279. It is a (fairly) hard problem we need to fix.

In the meantime - are you sure you want to revolve/lathe around the selected point parallel to the selected normal? It seems logical that you want to round off the whole "right front" side of the model (as displayed in the screenshot). If this is the case instead of the selected normal you should choose the "front right" edge or any other parallel to it.

[phkahler]

A crash is a bug. However... if I read that correctly you are doing an ill-defined operation. Revolve and Lathe will rotate around the normal vector. The normal in your picture appears to be pointing out of the sketch plane, and that means the rotation would be within the plane and not create a 3d shell. You may want to select the vertical sketch line instead.