It's done with the sketch layer, probably with Bixelangelo 2.0 There are some examples in this gallery under image browser the sketch tab.
Michiel is it possible to make a perfect circle with bixangelo, would be nice to have or some other standard perfect geometric shapes to play around with.
I know you "cheated" with the show below
komies, 11 years ago
Bixelangelo can't create 3D sketches. All 3D splines published in this gallery and as part of BixPack template packs have been generated by a script. This is a little application written to generate the spline.
Maybe this tool by Yousef is what you are looking for:
michiel, 11 years ago
Note that you can use the 3rd slider of the SHEARING property of the sketch layer to create a simple 3D effect.
michiel, 11 years ago