I’ve seen that in the tools page (http://www.ludumdare.com/compo/tools/) there are Blender and Sculptris listed as 3D modeling tools but i would also suggest Caligari trueSpace 7.61, which is free since microsoft acquisition of Caligari, and althought discontinued now, it is still usefull.

Download page: http://www.caligari.com/downloads.html