This is but a quick demo on how to import 3D models created in softimage to be painted in photoshop. It is important that uv coordinates exist, so later you can export the textures.
One thing I´d like to mention it´s that to paint the model with a «texture» that´s on a layer superior to the 3d model you must «merge 3d» it with CTRL+ALT+E and thus the texture «stamps» on the model. This you can use to create unique textures mixing them with traditional tools like clone and lasso feathered selection. Really neat!