Hi wim,

> is there a simple way to create a multi step blend from one simple curve to another, like in Illustrator, but then in 3D?

Max recently posted a "morph curve" plug-in which I think does what you're looking for:
http://moi3d.com/forum/index.php?webtag=MOI&msg=6373.1


Or another way you can approach it is to build a surface and then extract curves out of that surface to get your in between ones, either by using Construct > Curve > Isoparm, or by setting up a bunch of lines and projecting those onto the surface by Construct > Curve > Project.

- Michael