Blender

Blender is about twenty years old now and is amazingly robust. Professional 3D software runs from several hundred to several thousand dollars. If you go through the feature list, it's quite amazing that it is freeware (Open Source GNU Public License). It has all the standard features of the professional programs with sophisticated modeling, animation and rendering. It even includes realtime 3D game creation. And yet, there's more! Import and export standard 3D file formats. Create standalone executable files to distribute your creations.

If you have ever wanted to try your hand at 3D, but were intimidated by the cost or the learning curve, jump into Blender.

http://www.blender.org/