Strange plan behavior

[vaaSNLDZ]

Hi all!!

I want to get plans in coordinate systems perpendicular to the tangent at the point of the curve, but I get some non-system value: at some point (?), the plan rotates along the Z axis by 180 degrees. Does anyone know why?
To get a vector, I tried nodes Curve.NormalAtParameter and Curve.TangentAtParameter.

[sovitek]

Hi @vaaSNLDZ here is a fast way…could probably help…