More than 6 years passed since Pāvils Jurjāns made his «dynamic shape» tutorial in 2001. Today, we have many 3D engines for Flash. Free engines are listed below, in alphabetical order. If you happen to know another free engine, let me know.
3Dfs [1]
AS3D [1] [2] [3]
Away3D [1] [2]
CandyDimension [1]
FIVe3D [1], unofficial AS3 port [2]
Mx3d [1]
Nulldesign 3D engine [1]
Papervision3D [1]
Project3D [1]
Sandy [1]
Smart3D (packaged with CubicVR) [1] [2]
SWFZ [1]
Wick3D [1] [2]
WireEngine3D [1]
There are also two special FPS-oriented engines that deserve to be listed separately: