Ptex baking calculates and saves out material and lighting information to texture files that can be loaded back in without the need to set up UV mapping for the objects in the scene. The result of the baking process can be saved as a .ptx or .vrmesh file. Saving to a .vrmesh file (V-Ray proxy) generates point clouds to store the geometry and writes the shading information to a vertex color channel that can be read using the V-Ray Vertex Color texture. The following options are available when the texture baking engine is set to Ptex Baking.
UI Path: ||Render Settings window|| > Common tab > Baking Engine Settings rollout > Ptex baking options button (when using the Ptex baking engine)
