“This work is fully modeled and rendered in Cinema 4D. I have used BodyPaint and Photoshop for the textures. I start modeling the snail shell, to do this I use a spiral spline and a circular shape inside a sweep NURBS, I activate it and adjust the spiral parameters to get both the necessary turns and the thickness at the beginning and at the end.”
http://www.cgarena.com/freestuff/tutorials/misc/supersnail/index.html