Circles around a curve + DivideCurve : changes in orientation

Simple question that is driving me crazy, how can I avoid this to happen?

The vectors are oriented in a single direction, but the circle is drawn with a different orientation depending on the vectors direction. I was doing this in Python in order to make several spirals around a curve but I'm blocked with this problem.

Replies to This Discussion

Permalink Reply by Hannes Löschke on March 15, 2012 at 6:55am

The tangent vector isn't enough to define consitent frame (coordinate system). CNR guesses the plane on which to create the circle on fron the world coordinate system.

The PerpFrame constructs a perpendicular frame from tangent and curvature vecors. This should be consistent for your example.

On the other hand, you could find the CurveCP for each curve and a reference point. Then shift the circles seam with the Seam component

Permalink Reply by David Andres on March 15, 2012 at 11:25am

Thanks for posting. The PerpFrame gets the same result. I've managed to do it using as you said CurveCp and Seam, with another reference curve to get always the lowest coord Z point. It does the work.

If anyone know a simpler way to do it I'm all ears.