Brigade 3 real time path tracing engine revealed!

Fuck resolution. Noise is the topic of the future! Although I have a feeling some people will not understand what's going on here.

In short, this is a real time path tracing engine running at 30fps and 720p in real time and has been in development for roughly 5 years. To me and others who understand what they have achieved, this is absolutely astonishing. You will see noise as the ray tracing engine converges. It also runs at 720p. Despite that, this engine crushes Titans.

And yes true next-gen will actually start at 720p. And despite that fact, once we have GPUs that can clear up this noise, games will look more clear and pristine, more technically impressive and more realistic than ever and compared to what we're currently accustomed to even at much higher resolutions. You will get a higher geometry count than you have ever seen in anything other than CG. You will get lighting effects only previously possible in CG. And you will get all the materials that devs currently shy away from showing in video games or that generally look bad...mirrors, glass, water and other fluids, transparency, shiny surfaces, fully dynamic lighting engines, indirect lighting, etc. Standard.

Brigade 3

Time for an update on Brigade 3 and what we've been working on: until now, we have mostly shown scenes with limited materials, i.e. either perfectly diffuse or perfectly specular surfaces. The reason we didn't show any glossy (blurry) reflections so far, is because these generate a lot of extra noise and fireflies (overbright pixels) and because the glossy material from Brigade 2 was far from perfect. Over the past months, we have completely replaced the material system from Brigade and replaced it with the one from OctaneRender, which contains an extraordinary fast converging and good looking glossy material. The sky system was also replaced with a custom physical sky where sky and sun color vary with the sun position. We've had a lot of trouble finding a good way to present the face melting awesomeness that is Brigade 3 in video form and we've tried both youtube and Vimeo at different upload resolutions and samplecounts (samples per pixel). Suffice to say that both sites have ultra shitty video compression, turning all our videos in a blocky mess (although Vimeo is still much better than YT). We also decided to go nuts on glossy materials and fresnel on every surface in this scene, which makes everything look much a lot more realistic (in particular fresnel, which causes surfaces to look more or less reflective depending on the viewing angle), but the downside of this extra realism is a lot of extra noise.

The scene in the video is the very reason why I started this blog and is depicted in one of my very first blog posts from 2008 (see http://raytracey.blogspot.co.nz/2008/08/ruby-demo.html). The scene was created by big Lazy Robot to be used in a real-time tech demo for ATI's Radeon HD 4870 GPU. Back then, the scene used baked lightmaps rendered with V-Ray for the diffuse lighting and an approximate real-time ray tracing technique for all reflective surfaces like cars and building windows. Today, more than five years later, we can render the same scene noise free using brute force path tracing on the GPU in less than half a second and we can navigate through the entire scene at 30 fps with a bit of noise (mostly apparent in shadowy areas). When I started this blog my dream was to be able to render that specific scene fully in real-time in photoreal quality and I'm really glad I've come very close to that goal. We plan to show more videos of Brigade 3 soon, so stay tuned...

Now we just need to demand that AMD and Nvidia stop putting out rasterized based GPUs at $700+ and actually make a GPU that cleans up this noise. One more GPU generation, two tops, should do it, so late 2014 - early 2015. I have a feeling Maxwell will go this route. If they target compute rather than rasterized graphics, it could be just one and the Maxwell cards might just be the first to do the trick.

I'm actually running a GTX 500 series card which I chose over a 600 or 700 since Nvidia has cut back on the CUDA the last couple of generations and Blender ray tracing is actually faster with the older cards (I guess dual 480s is the fastest setup for Blender right now... actually I'm not sure about the 700 cards now that I think about it, my info is slightly out of date...) It still takes all night to render a 3-minute, 720p video. If they can get this running at any kind of decent frame rate with a high enough sample count to get rid of the noise, it'll look awesome.

Better make that 2 GPU generations:

Alex said...

Sam, which GPU areas specifically do they need to address?

Do you expect Nvidia's Maxwell series to do this and do you expect any additional benefits from the R9 290x?

October 23, 2013 at 12:05 AM

Sam Lapere said...

Anonymous: the demo was running on two GeForce Titan cards

Alex: I would say GPUs need hardware to improve ray coherency because thread divergence (where some threads in a warp take much longer than the others, effectively stalling the whole warp which sinks the efficiency) is a huge problem (maybe some ray sorting is possible in HW), to become more MIMD like, and to speed up ray traversal (intersections with the acceleration structure). Ray/triangle intersections (or ray/voxel if you want to do volumetric smoke) could be accelerated as well although. GPUs are already very fast at shading computations provided that ray coherency is preserved.

Of course, HW that can help building the acceleration structure on the GPU itself would be cool too. The Maxwell GPU should have a minimum of 4 ARM CPU cores on the same die as the GPU, which might alleviate some of these problems. Especially animated scenes should benefit from these architectural novelties. But it will also be possible to do much more funky stuff than just pure path tracing.

I don't know much about the R9 290x, but based on pure compute throughput numbers I'm pretty sure it should be a lot faster than the Titan for path tracing.

http://www.blogger.com/comment.g?blogID=7277449027963623452&postID=2683136081870909873&page=1&token=1382520622954

Holy shit.

Edit: Another video:

Godly reflections. It's pretty incredible what path traced lighting does, whenever he stops to let the noise clear, Nvidia and AMD need to step their game up and get these boy some cards that can run this engine. Chances are we will probably see it noiseless on a cloud first though before a standalone GPU.