Friday, August 1, 2008

Otoy, Transformers and Ray Tracing

After the Ruby/LightStage demo, 4 other video's appeared as part of an article about Otoy on TechCrunch. Urbach explains that he started experimenting with Renderman code on graphics hardware during the making of Cars in 2005. This work caught the interest from ILM, who gave Urbach the models from the Transformer movie to render in realtime. Urbach and his team made 4 commercials for the Transformer movie that were rendered and directed in realtime on graphics hardware. Afterwards, he was contacted by Sony to work on the Spiderman movie.

The 4 video's:

Video 1 OTOY Demo

This video shows short clips of realtime rendered Transformer sequences

Video 2 Jules Urbach explains OTOY's real-time graphics rendering

In this video, Urbach talks about his experiments with GPU ray tracing in 2005, the Transformers trailers and the voxel raytracing for the Ruby demo. For the tests with Cars in 2005, he was able to do "realtime raytraced reflections with up to 20 bounces of light". He also implemented some realtime global illumination technique. For the new Ruby demo, he is actually "raytracing the entire scene", and "not using the vertex pipeline anymore". Thanks to the voxel rendering "the level of detail becomes infinite".

Video 3 OTOY Graphics Rendered in the Browser

This video shows the server side rendering capabilities of Otoy. It shows Urbach interacting with scenes from the Transformers trailers, that are being rendered in realtime on his GPU servers and streamed over the net into the browser.

Urbach mentions "raytraced reflections on the windows". When he switches to nighttime, he says "in this particular demo, there's no baked lighting, nothing is precomputed", there are "hundreds of lights in the building rendered in realtime".

The demo runs on three graphics cards (3x RV770): one card renders the ILM Optimus, second card renders the G1 Optimus Prime and the third card renders the city and the raytraced reflections on the windows.

Video 4 Jules Urbach of OTOY Explains LightStage

Video about LightStage, slightly more elaborate than this one.

There is also a video of the full AMD Cinema 2.0 event in which Urbach talks a bit about ray tracing on GPU's (from 41:00 to 47:00) and goes a bit more in-depth during the Q&A session (from 72:00 to 88:00):

- Urbach has been talking to game publishers to start integrating the relighting part of Otoy in existing game engines

- Otoy can do full raytracing, but also supports hybrid rendering. It can convert any polygonal mesh to voxels

- The Ruby demo does not use any polygons, only voxels

- For games, Urbach thinks hybrid rendering will be the way to go "for a very long time"

- With this technology, game developers will require a different way of working. Basically they're saying that you can make a photorealistic game, but the workload on the artist side will be astronomous

- In 2005, Urbach started out writing approximations to Renderman code during the making of Cars. At the time, he used cheats for ray tracing and reflections. In three years, GPU’s have evolved so quickly that the latest hardware makes realtime ray tracing possible that is “99 % accurate”

- Voxel data sets are huge, but with voxel based rendering you can load only subsets of the voxel space, which is not possible with polygons. You can also choose which texture layers to load

- Compression and decompression of the voxel data is CPU bound. What takes 3 seconds to decompress on a CPU, can be done at a “thousand frames per second” on a GPU.

- What's interesting according to Urbach is that in 2005 he started out writing approximations to ray tracing, but the latest generation of hardware allows him to do ray tracing that gets really close to the 100% point

Urbach also showed another Otoy demo at the AMD event, called Bug Snuff. It shows a photorealistic scene with a scorpion, rendered in realtime and directed by David Fincher. Really impressive stuff!

Lastly, the ompf thread where it all started:

Thanks to all the ompf members and guests who participated and contributed to the thread.

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