Disney Goes Open Source with Ptex
Walt Disney Animation Studios (WDAS) has launched an open source site (www.disneyanimation.com/technology), allowing users for the first time to access in-house software.
The first software available is WDAS's acclaimed texture mapping system, Ptex, (http://ptex.us/). Ptex was developed by WDAS Principal Software Engineer Brent Burley for use in production quality rendering, and is being driven to become adopted widely in the community by WDAS Director of Technology Dan Candela. WDAS has also compiled a set of papers available on the site for sharing additional technical innovations that will benefit the industry.
With the increase in render complexity requirements in animated film, the WDAS team found that standard texture-mapping methods being utilized had become inefficient and complicated for artists to use. In an effort to increase the efficiency and quality of texture mapping on complex and intricate geometry, Burley spent a year developing the Ptex software. Overseen by Candela, the Ptex system has already been licensed to multiple vendors and studios (such as Sony Pictures Imageworks and Weta Digital), and is now utilized on all projects at WDAS.
Ptex introduces a new texture mapping method that has benefits for film production. It eliminates the need for tedious and labor-intensive UV assignment by applying 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, resulting in a significant reduction in server load. The Ptex API provides cached file I/O and high quality filtering -- everything that is required to easily add Ptex support to a production-quality renderer or texture authoring application.
This, of course, is part of a growing industry trend toward standardization. Imageworks recently released the Alpha version of its source code for its Open Shading Language (OSL). And GenArts, which partnered with Lucasfilm last year, has expanded its software portfolio with recent purchases of The Foundry's Tinder and Tinderbox plug-ins (and with an eye on future Nuke collaboration) as well as wondertouch.
"Probably one of the biggest questions that people ask us is, 'Why is Disney doing this'?" offers CTO Andy Hendrickson. "Part of the open source strategy is that there is a lot of software that a studio builds and a lot of studios build the same exact software over and over, and certain parts of that software are not part of our secret sauce in making images. Certain parts of it make sense in sharing it with other people so we all don't have to recreate the wheel. Now Ptex is one of those that is unique, novel and groundbreaking. But, ultimately, it would be better to share than hold in-house because it helps all of our folks in the industry so much more and we get such good will than keeping it private. So we decided to do that. And in the process, we looked at other pieces of technology, and thought these would be better to share than to keep in-house also. Right now the only other one available is Pythoscope (a unit test generator for programs written in Python), but we're hoping to have a couple more done in time for SIGGRAPH."