As this function has existed in V6 (for all I know in prior versions of C3D) I would imagine that reinstating the flat tangent should be a minor matter.
I do hope that the Good Doctor considers this request. As I pointed out, starting any transformation (position / rotation / size) with a flat tangent is the standard in in physics.
Twiddling a spline is a PITA :frown:
Thank you, Martin.