Shading at Siggraph 2017

This summer downtown Los Angeles got hotter, with awesome progress being presented at Siggraph left and right. Here are some oh my highlights in the world of shading.

MaterialX goes Open-Source

Years ago, I remember sitting down in the lounge of a hotel in Anaheim. Sitting with me were friends from Industrial Light and Magic, The Foundry, and several film and software studios. We discussed how hard it is to share material descriptions across software and studios, and have them look right, without having to hand off all the secret renderer sauce.

ILM really took the helm in this effort, and came up, year by year, with a better and more refined spec, called MaterialX, for a standard in pattern descriptions. Used alongside Alembic, MaterialX helped them share assets with vendors, and across OpenGL based software such as Mari, and final render quality. And now, the spec is mature enough to go open source. Congratulations!

Back at Pixar, I have looked at this spec quite a bit, and worked with our friends at ILM to try to improve it and make it converge with our Universal Scene Description (USD) shading libraries, which in turn were heavily influenced by MaterialX. As a result, it's easy to see a near future where MaterialX will be natively encoded in USD.

I will get deeper into this in a separate post, but a somewhat similar goal was set by NVidia's Material Description Language (MDL). NVidia has put some real muscle behind this project, which is already established in other industries, such as product design, automotive, architecture and even fashion. MaterialX differs from MDL in its focus on film-centric problems, such as flexible deferred binding and color spaces (which can become a problem when handling different hardware and cameras). It is also very focused on pattern network definition, while MDL has successfully captured the physically accurate illumination side of the equation.


Flow Graduates

While Coco is still in its final stages, our new single-asset shading tool Flow (see a couple of posts ago) is getting more mature, and is getting used in both characters and sets in newer shows.

Come see my friends Florian Hecht and Peter Roe present the fruits of our labor at the Nvidia booth on Wednesday at 10am. Or at the Renderman Science Fair, if have an invitation.
[update] Here is the link to the talk at the NVidia booth.

A lot of Flow's success in production can be credited to the speed and accuracy of our Optix-based preview renderer, called RTP. This prototype has shown a lot of potential and we hope it will prove useful to our team in Seattle, to continue to push Renderman speed.

We also focused on streamlining the most common operations, leaving the more complex things to Katana. As a result, accurately shading assets can take hours, where it used to take days.

But really, Flow and its level of integration across our complex pipeline wouldn't have been possible if we didn't have a such a powerful scene description as USD.

Renderman Advancements

Renderman's core tech advances are also nothing to laugh at either. Much faster curve rendering, which can make a difference where everything is furry, hairy or even just a bit fuzzy. Newer, better subsurface and denoising techniques are available, in use already at Pixar. FxGuide just published a great article with a deep dive in path tracing and subsurface, featuring our work, especially that or Christophe and Ryusuke.

Cars 3 Production Sessions

Top research and academic papers are what have historically distinguished Siggraph from other events, but Production Sessions and panels are still some of my favorite things to watch. This year we are presenting Cars 3 in all its beauty.

My friends from technology, art, characters, sets and lighting are showing some of the remarkable work that went into it - including the deferred texturing techniques mentioned earlier. Scratches and bump/roughness interactions are not new concepts in rendering, but their quality leaped ahead with new authoring techniques.

Smash and Grab

Pixar also has an experimental department that tries new things, not for theatrical consumption, called Spark. This year the group, only a handful of part time artists and TDs with no Pixar pipeline set up, put together a beautiful little short, called Smash and Grab. There is a talk about it on Wednesday at 9am. Hope you can make it!

and much more...

Trying to cover everything noteworthy that happened this year is well beyond the scope of this post. But I did see some exciting news about Epic's new DataSmith Alembic-based toolkit, as well as Allegorithmic's impressive new Substance/Unreal integration.
Faster workflows, standard exchange and simpler controls seem to be the focus of this year. The near future of shading is getting brighter, and that makes me smile.
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