Panda3D is a 3D Engine built on top of python. Blender can run python scripts. You can type them up and run them right in the program. I'll be using it eventually to write my own file format export scripts.
3dsmax supports python as well and just like in mel (maya) you can combine python with maxscript. I heard some developers saying that often they would code core functions and classes in python and with mel/maxscript/blender python they would then add the final interfaces or integration into the 3d tools. Just on a…