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The reasons GPUs aren't yet used much in the VFX industry, are: GPUs are currently limited by what they can do - they're fast in terms of float throughput in a

by berkut 15y ago

The reasons GPUs aren't yet used much in the VFX industry, are: GPUs are currently limited by what they can do - they're fast in terms of float throughput in a simple loop, but as soon as you introduce a lot of branching (for things like global illumination - path tracing), their throughput falls off a lot. The Fermis are better, but Intel's branch predictors are very good. SSE and AVX can also more than quadruple the throughput of CPUs in the best of cases. Also, a typical VFX feature film scene can have up to 200GB of geometry and 100 GB of textures, and this is before acceleration structures, deformation motion blur caches and texture mip-maps have been created. Transferring that amount of data through the PCI-E bus isn't worth it at the moment, especially given the limit of 6GB of onboard VRAM that would mean huge amounts of swapping. Also, GPUs use even more power and produce even more heat than CPUs, so you don't save anything here.

Keyframe 15y ago
One other reason why GPUs aren't as widely used: Primary Rays Cache, Secondary Rays Trash! GPUs are becoming a standard in some pipeline stages of rendering though. http://www.nvidia.com/object/wetadigital_avatar.html http://www.nvidia.com/object/wetadigital_avatar.html
- berkut 15y ago
  That's Weta being weird and being wed to their PRMan pipeline using PantaRay as a first-stage radiosity solution which is fed to PRMan as an infinite series of lights. It works, but from what I hear it's limiting their pipeline quite a bit. But then, they're Weta so they're more than capable of writing their own stuff and they're good at what they do :) ILM used to do something similar, but a lot of the big houses are moving from PRMan over to raytracers (specifically Arnold) with full GI support as it makes the overall pipeline and definitely artist look-dev a lot simpler and faster. PRMan 16 is also a very good raytracer now (it could previously do ray tracing through custom shaders).

by berkut 15y ago

Keyframe 15y ago

One other reason why GPUs aren't as widely used: Primary Rays Cache, Secondary Rays Trash! GPUs are becoming a standard in some pipeline stages of rendering though. http://www.nvidia.com/object/wetadigital_avatar.html http://www.nvidia.com/object/wetadigital_avatar.html

berkut 15y ago
That's Weta being weird and being wed to their PRMan pipeline using PantaRay as a first-stage radiosity solution which is fed to PRMan as an infinite series of lights. It works, but from what I hear it's limiting their pipeline quite a bit. But then, they're Weta so they're more than capable of writing their own stuff and they're good at what they do :) ILM used to do something similar, but a lot of the big houses are moving from PRMan over to raytracers (specifically Arnold) with full GI support as it makes the overall pipeline and definitely artist look-dev a lot simpler and faster. PRMan 16 is also a very good raytracer now (it could previously do ray tracing through custom shaders).