Hi everyone,
I having an issue with the Skin POP. I have lines with a lot of curvature, and I add circles at each point along the lines, oriented in the direction of the line. When I apply the skin, it does something strange and I can’t figure out how to fix it. Maybe someone knows? What I’ve noticed is that it shows up when the curve is very sharp or the circles are very small.
SkinProblem_2025_32460.toe (7.5 KB)
I’ll bookmark this topic, as I met the issue (flipping normals / Frenet Serret frame - beware this is kind of a rabbit hole) but not the solution, sorry.
The idea would be to calculate your orientations based on more than just the previous or next point to avoid 180 or 360° flips… But I don’t really know what I’m talking about 
Hello @pao.olea
There’s an orientation flip happening at the Copy POP. The operator computes an orientation that satisfies the target direction vector, but it doesn’t take into account the orientation at neighboring points. That’s why you see discontinuities when the curve bends sharply.
To get a continuous frame along the curve, you need to propagate an orientation from point to point while rotating it as little as possible—essentially a Rotation Minimizing Frame (RMF). At the moment, there isn’t a simple built‑in solution for this, other than implementing the RMF algorithm yourself, for example in a GLSL POP.
The good news is that in the next official release, the Line Metrics POP will be able to compute a continuous orientation frame along line strips. The Copy POP will also support using this rotation data directly, giving you smooth, stable orientations along the curve.
Thank you so much! With this info I was able to build a GLSL and solve it. Really appreciate it!
