create a surface shader in the hypershade and then in the attributes of the shader is "matte opacity" drag it to black. this will render the object as black with no alpha channel. which is basically a silhouette. your shadows should have an alpha so you can comp them, so that should be that... i guess!

i think this is basically what you are trying, i have a shake script in this thread if it helps -> https://forum.simplymaya.com/showthre...threadid=31769