I want to model the handrail of a helical staircase. When I sweep a circle along a helix in FreeCAD, the result is very inconsistent and for example depends on the diameter of the swept circle. While in my example I sweep a simple Draft->Circle along a helix, the exact same is happening when I draw the circle in a sketch (I guess internally those two things are same in FreeCAD).
Here’s the result of sweeping three circles (30mm, 75mm, 150mm radius resp.) along the same helix (with the sweep moved in z direction).
broken_helical_sweep.png
broken_helical_sweep_tree.png
Changing any of the sweep properties (Solid, Frenet, Transistion) does not change the outcome.
I did search the forum and the closest thing I found was this: https://devtalk.freecad.org/t/sweep-part-wb-problem/51367/1
But changing the tesselation settings, as described in that thread, didn’t change anything either (btw. I change those settings sometimes anyway for mesh exports for 3D prints).
That seems to be the solution. Thank you! The annoying thing: I played with the segment length value while trying to get the swept helix to be rendered correctly, but I must have had an unfortunate combination of values, because it wasn’t fixed by that at the time and dismissed that as an option.
This was also what i thought, but sometimes in sweeps in PartWB had still this issue. When i look on the example file, then yet (pretty late) i get the idea, that it have something to do with the section area to length ratio.
