First you have to use the inner faces, not the edges, but it is more complicated, and finally it may be no issue at all.
... and turn the clone Job->Model->Extrude by 90° around Z axis, then FreeCAD crashes immediately when leaving the field which induces a recompute. If I remove the Helix operation before turning there is no crash.
Even tough this works most of the time ATM, relying on the tessellated surface having a polygonal maximum in the x direction as the current code dose is fragile and may break at any time if the tesselation algorithm is changed, or the assumption is wrong for other reasons, like rotation after tesselation. Therefore i have the following PR: 2416 this fixes all test cases in this thread for me. Please test.mlampert wrote: ↑Sat Aug 10, 2019 5:47 pmI'm not able to reproduce the issue other than verify that your file @chrisb does have that issue.
Attached is the file I used to create some unit tests. They rotate the body in 5 degree increments and the resulting helices are all correct. They also rotate the Job's model clone in 5 degree increments and the results are also correct. Finally, the create a clone of the Body, rotate the clone in 5 degree increments and generate helixes based off that - also all of them correct.
I will not push the tests as they are since they add ~30 seconds of unit test runtime to our build, so for the final PR I'll reduce the test samples. But if anybody wants to have a look, and play with it the tests are in github