I've already posted this in the Lingo forum but as it works
in 3D as well, I thought I'd also post it on this forum.
We’ve just released a new Xtra:
The Minds Eye BézierCurve Xtra contains a set of Lingo
functions for generating Bézier curve points for drawing or
animating. You can draw pre-defined or random curves in realtime or
you can set a sprite animation to follow Bézier positions.
It also works in 3D! You can create 3D Bézier Curves or
you can animate a 3D object travelling along a Bézier path
(see the example Director movie in the full evaluation bundle)
It also allows you to import 3D splines or animation paths
from 3D Studio MAX. The full evaluation bundle contains a MAXScript
file for exporting lines to XML. The BézierCurve Xtra contains
3 functions for importing the XML file data.