When we are trying to ray trace hair, do we compute intersection with each individual hair? If so, will that be super slow and expensive (consider people have millions of individual hair)?
mcjch
No, you're right I don't think we do because of time and cost. Here is NVIDIA OptiX: https://developer.nvidia.com/rtx/ray-tracing/optix which renders hair and fur for programs. In this blog: https://developer.nvidia.com/blog/optix-sdk-7-1/, they describe how NVIDIA utilizes geometric curve primitives to handle ray tracing hair strands.
Unicorn53547
So the Kajiya-Kay model is not physicc-bases model as it did not take transmission into consideration insode the hair fiber. Question is that, how do we deal with different hair color or light source? Wouldn't this model need some prior knowledge to do real rendering?
When we are trying to ray trace hair, do we compute intersection with each individual hair? If so, will that be super slow and expensive (consider people have millions of individual hair)?
No, you're right I don't think we do because of time and cost. Here is NVIDIA OptiX: https://developer.nvidia.com/rtx/ray-tracing/optix which renders hair and fur for programs. In this blog: https://developer.nvidia.com/blog/optix-sdk-7-1/, they describe how NVIDIA utilizes geometric curve primitives to handle ray tracing hair strands.
So the Kajiya-Kay model is not physicc-bases model as it did not take transmission into consideration insode the hair fiber. Question is that, how do we deal with different hair color or light source? Wouldn't this model need some prior knowledge to do real rendering?