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Comment by Anotheroneagain | Hacker News Reader

I believe that results like these show that our algorithms are woefully inadequate, and something much faster has to exist, if a NN can do so much better with all the overhead.

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This isn't efficient at all. It requires a 3090 to get 60fps - and presumably it requires all the GPU's power to do that for the simple scene in the article: a couple of sheets and cushions on a sofa.

Possibly it's RAM rather than compute limited but still. You couldn't use that in a game. Existing techniques like PBD or verlet integration would be far more efficient.

Maybe on future devices with separate neural processor units this could be useful. But even then I bet those same chips could run standard real-time cloth algorithms really really fast too.

Edit: I downloaded their video and there's no movement at all, only still images. Maybe I misunderstood the purpose of the technique. But I re-read the article and it certainly seems like they're claiming to do full simulation, not just static scenes.

That scene with the sofa isn't even getting 60fps! It kinda feels like a disingenuous article after watching the video.

I don't see how something like PBD helps at all with rendering.. are you thinking that this work relates somehow to physics simulation? Considering that the result is pretty much just a shader, I imagine it works just as well on animated scenes as static ones.

Well, technically cloth simulation and cloth rendering are separate. But in real-time rendering the terms are often (generally, even) used interchangeably - it's rare that you'd just want static cloth without movement - so at the very least I'd expect a sentence or two clarifying that they don't do any movement simulation here, it's a pure light transport technique.

Light/material calculation in shaders requires exponentiation, which is a costly operation. If a clever lookup table can get around that, it sure can be faster.

Using a lookup table[1] or other approximations like wavelets[2] for complex BRDFs is a well-known strategy.

[1]: https://github.com/HectorMF/BRDFGenerator

[2]: https://hal.science/hal-01518547/document

Yeah it’s kind of like a FPGA implementation: it proves the concept but is by definition not optimized for efficiency. There must be a way to go from the weights to an algorithm.

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