Path Tracing

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Begause Benis. :DDD

>>61450245
isn't path tracing horribly inefficient compared to ray tracing? ? what did they do differently?

>>61450303
I have no idea that's why I'm on /g/ this tech looks amazing

>>61450312
ye but how does it work? their site is offline

>>61450380
I think it emulates actual photons and calcuates brightness off each surface they reflect

>>61450398
wow, tell me more sherlock

Because it requires an insane amount of compute power to get a decent framerate and have enough samples to not get drowned in noise.
Also it is a thing already, see Octane or blender's Cycles. The framerate is just not interactive enough for MUH GAYMES but it doesn't matter much because real-time PBR engines are getting pretty good as well.

>>61450303
Path tracing is physically accurate, ray tracing isn't. With path tracing you automatically get things like fresnel reflections/refraction or global illumination. With raytracing you only get the direct lightning and you then have to modify your rendering engine to support other features that add to photorealism but these other features will only be physically unrealistic hacks.

Path tracing is a pretty fun subject, here's some recommended reading.
http://www.pbrt.org/
http://luthuli.cs.uiuc.edu/~daf/courses/cs-419/Week-6/complexpaths2012.pdf

And a higher-level overview of the rendering equation which is a bit more accessible.
https://www.youtube.com/watch?v=pjc1QAI6zS0&list=PLujxSBD-JXgnGmsn7gEyN28P1DnRZG7qi

>>61450559
I understand how path tracing and ray tracing work in principle. I know that ray tracing is much faster but still requires extra algorithms to implement highly realistic rendering.

I'm curious how the engine from the video works. I found this link: http://wccftech.com/brigade-nvidia-gtc-presentation-realtime-path-tracer-engine/

A few quotes:
>Whenever a ray hits a surface, a new ray is traced from that hitpoint in a random direction until the max path depth is reached or until a Russian roulette-like mechanism kills the ray.
using a roulette filtering seems quite interesting

>special scene-graph optimizations that are unique to Brigade
>Instancing is one of the most powerful features of Brigade.
instancing allow it to deal with large scene which have large number of a few meshes. We can already see a downside: having a large variety of meshes will hamper it's performance. I think Euclideon did the same trick with instancing.

>Because Brigade uses a very specific custom acceleration structure
this is what I'm curious about

>>61450425
just draw a penis on your forehead and call it a trace.