Zbrush. An amazing 3d sculptign tool. If Mays is Art- Cad is Math - Rhino is the middle... then Zbrush is near Rhino. Much easier than Maya, and very powerful. Sculpting like input is unique and artist friendly. It's what most movie monster digital sculptors use. Fast and intuitive to create highly organic forms with great detail. Not so good for making a precise gear- like CAD. I am a fan but not a user.