Ptex is a texture mapping system for production-quality rendering: no
UV assignment is required. Ptex applies a separate texture to each
face of a subdivision or polygon mesh. The Ptex file format can
efficiently store hundreds of thousands of texture images in a single
file. The Ptex API provides cached file I/O and high-quality
filtering -- everything that is needed to easily add Ptex support to a
production-quality renderer or texture authoring application.