You wait for ages, then 2 open source vfx releases come along at the same time!

Disney Animation Studios’s 3d paint format and API Ptex is available to download.  Ptex avoids the need to UV complex meshes by saves out a set of texels for each face of a subdivision surface. These are independent, so it is possible to have different resolutions on adjacent faces. It does rely on adjacency information to filter across face boundaries, so you need to transfer your texture if mesh topology changes. I think it also only works if you have quadrilateral faces. Hopefully this will be picked up by the popular 3d paint packages soon – the author of 3D Coat has started experimenting with ptex.

And Sony Picture Imagework’s has released the first specification and code for Open Shading Language. This is a set of libraries and a compiler that can be used in any rendering engine, and will be used in SPI’s internal renderer – developed from Arnold. The language has been designed for raytracing from the start, and introduces the concept of radiance closures. These are functions that return a sampling pattern based on the material BRDF to the renderer. The renderer can then bundle coherent rays from several materials together to exploit raytracing caches better. Shaders can be linked in a similar fashion to coshaders, although the language does not define a scene description API (like RIB or mi) so the implementation is up to the renderer developer.

They also have some things which should have been added to RSL a long time ago such as more string tools, runtime determination of varying vs uniform variables, and arbitraryderivatives.  They also have an interesting approach to secondary outputs called Light Path Expressions. This uses regular expressions to express which ray types you want in your secondary image. This looks powerful, but also a bit intimidating.

There is a good introduction to OSL by the lead developer, Larry Gritz, and a story by fxguide here.

Dan Bethell and Johannes Saam released RmanConnect today. This is a RenderMan display driver and Nuke node which communicate over TCP/IP so that you can render directly into Nuke. This has been primarily been developed for 3Delight, but should work with other RenderMan renderers, such as Prman. The source code has been released under a BSD license. Also Libero Spagnolini has an impressive shader building tool called  Shaderlink available to download which is built around 3Delight and PyQT. 3Delight itself was recently updated to version 9.0 and 3delight for Maya to 5.0. Highlights include support for Maya 2010, an unlimited thread license, multi-camera rendering and RIB fragments – see all the changes in the changelog.

Also the openSourceVFX.org website opened recently. This is intended to be a central portal of open source VFX projects and is being run by Larry Gritz, Chad Dombrov and Philippe Leprince. their goals include listing and presenting valuable open-source projects for the VFX community and giving a voice to OS project leaders and VFX pros to promote their work and keep us updated.