There's no way to render thick outlines etc. in Cheetah 3d (because it renders the back faces of polygons).
With post-processing you can use filters like Photoshop's Accented Edges (this works even better if you use materials specifically to make picking out the object boundaries easier).
For realtime 3d, you can create a larger "shell" around the model, flip all the normals in the shell, and set it to be desired outline color (usually black).
All of this is a pretty poor substitute for a proper toon / cel renderer or shader, unfortunately.