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The author is not doing a good job of differentiating ordinary ray tracing with path tracing. It is path tracing that actually gives all of those wonderful rend
by _hypx 4y ago
The author is not doing a good job of differentiating ordinary ray tracing with path tracing. It is path tracing that actually gives all of those wonderful render effects "for free." Ray tracing by itself isn't that impressive. But we are a long time away from path tracing being a widespread and practical rendering method.
The big worry here is that nVidia is pursuing the equivalent of internet streaming video in the 1990s. Sure, eventually the technology will get there, but that could far enough in the future that nVidia will be disrupted or displaced long before it is a reality.
- yazzku 4y agoIt also accuses rasterization of being "a hack", as if 1 spp with the denoiser coming to the rescue was nothing of the like. Also no need to label things as "hack"; they are all approximations, and good ones at that. It also then argues that developers get RT "for free", which is nothing of the sort since there are many details involved to get it to work decently.
- Negitivefrags 4y agoCurrent RTX hardware is rather lame to only get to 1spp isn’t it? It’s not even clear that it’s the right approach. A graphics engineer I know has this to say about it. “Telling me you made hardware accelerated BVH is like telling me you implemented hardware accelerated bubble sort.”
- yazzku 4y agoI don't think real-time ray tracing is lame. Diffuse is low-frequency and redundant, denoisers work magically well. It's 1spp per frame, but the denoiser is essentially allowing the application to distribute the workload across frames. For perfect specular a single ray is sufficient, and glossy is somewhere in between the two. The limitation doesn't have to do much with firing more rays than handling more complex materials; what I just described decouples diffuse/specular and is how games are doing it these days. But if the current materials are plausible, then what's wrong with this approach? I do think it is the/a right approach... when used judiciously and when an alternative rasterization approach doesn't already exist or has obvious flaws. For example, some games use a hybrid SSR-RT reflection; do the SSR first, then fire rays where the SSR misses (insufficient information in screen-space.) I think the UE5 Matrix demo does this. You kind of get the best of both approaches. The article in this sense proposes a false dichotomy; to choose between the complex "hacks" of rasterization, or the easiness of RT. Except that rasterization has decades of research and solutions are well-known and already implemented, and RT is not 'do the dumb thing and let the hardware do the work'. I don't think BVH construction is as bad as your friend paints it. There are semi-parallel approaches available, i.e. https://www.researchgate.net/publication/327216026_PLOCTree_A_Fast_High-Quality_Hardware_BVH_Builder https://www.researchgate.net/publication/327216026_PLOCTree_...
- ahartmetz 4y agoI am no fan of nVidia, but yes, rasterization is a hack. I like to call raster GPUs overglorified sprite rotoscalers. Every little thing that light does in reality, except perspective, needs to be painstakingly implemented in dedicated code. Path tracing is much closer to just modeling what light does, and all the optical phenomena fall out of it naturally.
- phlipski 4y agoOne man's "hack" is another man's "elegant solution".