Blender is an open source, therefore free, 3D creation suite, it is used to create models, animations, simulations, almost anything in 3D.
Blender, by itself, does not support meshes in the BZW format. To get BZW compatibility, you must install the BZW Toolkit, provided by Teppic. The BZW Toolkit supports most BZW options, but sadly is not 100% complete when it comes to BZW map creation.
You can find more info about the BZW Toolkit Here
You can also get BZW meshes by exporting a .obj mesh from blender, and Running it through modeltool.
Now, Blender's interface is quite a bit different from any other program that you may see. Most of the controls are located in the bottom portion of the screen, and some can also be activated by pressing and holding the spacebar for about 1 second.
Blender has a few default objects, such as:
- monkey. Yes, monkey. (Suzanne is her real name...)
You can also make almost any object in blender, by modifying the default objects. Check out the subsurf, array, and displacement modifiers.
You need to be careful in blender, because you can start adding up verticies and faces (the basics of a mesh) VERY quickly if you use subsurf. Keep in mind that BZW maps get very large (file size) at about 20,000 verts. I recommend keeping most maps between 15,000 and 20,000 as a max, because of downloads times, overall map running speed, and of course practicality. There is no point in making very detailed objects, when this can usually be achieved with textures.