Attached Link: http://www.ac3d.org/

See the above link...

AC3D is a shareware 3D modeller by Invis.

It's fairly basic, but it can make a good stab at most things. And that's one of its advantages. It's easy to learn. And being shareware, fairly cheap. Oh, and it comes complete with a (PDF) manual.
It's probably best used for making simple, non-biological things, but that might be my own fault - I've never really tried to make a biological model.

My own main uses for it are for whipping up simple props for Poser and/or Vue, and for creating/modifying dynamic clothing.

One thing it cannot do is create morph-targets for Poser - it changes the vertex order.

Cheers
Diolma