All of tool mentioned above r good,but i would say u stick 2 milkshape.Right now im using houdini,maya and 3dgs.Maya is the best especialy now when u have 3dgs 2 maya and opposit (well u have it for 3dsm but i never worked with it)but i had sam problems with default render in maya and editing emviroment solved only jalf of problem so i swaped 2 houdini witch is superb tool 2.