Disney has just release previously discussed PTex under an open-source (BSD) license and made it publicly available to all.

The new open source library supports Catmull-Clark subdivision surfaces (including quad and non-quad faces), Loop subdivision surfaces and polymeshes (either all-quad or all-triangle). Also, several data types are supported including 8 or 16-bit integer, float, and half-precision float. An arbitrary number of channels can be stored in a Ptex file. Arbitrary meta data can be stored in the Ptex file and accessed through the memory-managed cache.

The source code is available in a github repository, and you can watch a demonstration of PTex in use after the break.

Ptex Overview. via CGSociety