Monday, July 22, 2013

Real-time path tracing: ultra high detailed dynamic character test

To celebrate Siggraph, here's a new video of Brigade for your enjoyment, showing an animated character mesh consisting of 125k dynamic triangles rendered in real-time at 35 fps with path tracing (the static background contains 600k triangles).

To give some background: one of the main reasons why ray tracing has not been considered a viable alternative for rasterization as a rendering technique for  games is because ray tracing requires an acceleration structure to achieve real-time performance and dynamic scene support requires that acceleration structure to be rebuilt or updated every frame which has been a long standing and often revisited problem in the ray tracing research community.

Until a few weeks ago, Brigade was capable of handling about 50k (non-instanced) dynamic triangles at 30 frames per second. Recently however, the dynamic triangle budget was tripled and we can now do around 150k triangles at 30 frames per second (and this will soon increase further to a dazzling 1 milllion dynamic triangles at 30 fps), which allows for some extremely detailed deformable meshes like characters. VFX houses doing previs of real-time motion captured characters will love this.

UPDATE: Updated the post with a fresh batch of screenshots to show the extreme texture detail on the LightStage model.

HD video (rendered at 720p):

Note the huge difference diffuse color bleeding makes on the character's body when the floor is matte in the next two screenshots: 

The entire movie industry is going down the physically based rendering path with path tracers like Arnold. Recently even Pixar/Disney went with full path tracing for Monsters University and completely reworked their old Renderman renderer by adding a path tracing mode. The benefits of progressive rendering with physically based global illumination and materials without having to rely on time consuming point cloud baking has entirely revolutionized the way artists work as it's a game changer for the creative process. Games will eventually follow this path as well as game developers keep striving for cinema quality graphics as they've been doing since the introduction of the first OpenGL accelerator boards. And if you're still not convinced of the undeniable superiority of path tracing after all this fluff, you can talk to this nicely textured hand:


Btw, in case you haven't noticed yet, we dramatically improved the lighting quality and sky model in Brigade over the past months and it's now almost up to Octane standards.

More tests to come soon.