Rotate tangent plane at 3D spline

Long story short, how to make the profile follow XYZ plane at point but Y or X component being always parallel to horizontal plane? Taking only XY component of the tangent vector doesn’t help because then the profile is always vertical thus not anymore perpendicular to point on curve and some of the profiles rotates 180 degrees for some reason.

test.dyn (32.3 KB)


I post a technique at the bottom of the thread.

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is this what you want ?

pathtest.dyn (35.6 KB)

@Thomas_Mahon Thanks! The profiles are horizontal and follow tangent plane at curve but the profiles still getting 180 rotation…

Not exactly. The image above shows what i want but without the 180 rotation of course.

Not entirely sure I understand you, but this is a quite robust way to construct coordinatesystems:


@jostein_olsen Thank you! That did the trick.