Blender is a 3d program.
Blender is one of the few free 3d editors. While the program is very extensive and supports 3d rendering, animation and interactive 3d applications, it's main use for the Sims 2 is in creating static meshes, although there is now a smd import/export that can support boned meshes.
Blender is in constant development, with new options added with each version. As of January 2007, the program supports multiple groups, a uv-mapping tool, textures, etc. The interface is completely customisable and quite daunting for beginners. Because of the large amount of keyboard shortcuts, however, it is a very fast program to work with, once you get used to it.
Several modders in the community use Blender and offer support and tutorials for it, in addition to a large amount of helpforums and tutorials on the official Blender site, making the learning curve a little less steep.
- .smd (with plugin here)
- several others
Use in Sims 2 Modding
Blender's main use is for objects, both static and animated, since the program initially didn't support the smd files needed for bodyshop meshes. Bobcatben has created an smd import/export for Blender here
Traditionally - in order to make animated objects, you'll need to import the mesh groups in the Mesh Tool to assign the bones, and you can find tutorials for that method on site.