Lecture 13: Global Illumination & Path Tracing (64)
eugene-yoojin-han
Before getting to know about these concepts, eery time when I was doing 3D modeling with global illumination and path tracing enabled I wondered why it took so much time to render a single frame. Now I know why it takes an exceptionally great amount of time to render considering the amount of details captured when global illumination with a high number of bounces are enabled.
zy5476
Looking through all of these different bounce number renderings of the same picture got me wondering if there was an optimal or standard number of bounces that was normally used or "optimal"
KevinXu02
The image becomes brighter when there is more bounces, but it is hard to tell the difference between 8 and 16 bounces, which can be explained as the energy of light decays after bounces and the render recursion converges.
brianqch
I noticed that as the number of bounces increased, so did the overall brightness of the image. But I could also see that there is some increased noise and a few white artifacts that now appear in this image. Why is that the case? Look near the top lamp for example.
jinweiwong
Even though this image aims to replicate the global illumination that we see in real life, I tend to think that this looks less realistic because of artifacts noted in some of the above comments. For example, we see white noise close to everywhere and the whole scene just looks brighter overall.
noah-ku
It seems like it's important to have at least some extra bounces when it comes to global illumination. When we look at certain objects like the lamp or the glass bottles on the tables, it gets rendered correctly when we reach two or four bounces (they were originally just black). However, if we add more bounces, the image just becomes brighter and adding them doesn't seem too necessary.
ArjunPalkhade
For efficiency purposes, is the number of bounces constrained to perhaps 1-2? I feel like there are marginal returns on the later bounces of light, and so they can be sacrificed for performance.
sueyoungshim
Is there a limit to how many bounces the rendering should have? because in real life there seems to be infinite bounces of lights, but for some reason these photos appear to be more faded as the number of bounces increase.
Mehvix
@sueyoungshim I think the Russian roulette for global illumination (that we implement in proj2) could help tackle the issue of the under saturation while providing more information than reducing the number of bounces
Edge7481
@ArjunPalkhade That would mostly depend on whether you need it rendered in realtime or not. Video games tend to be limited to 1-2 bounces or use other methods to approximate this behavior like ambient occlusion. CGI in movies can take as long as needed and can range from 3-10+
Before getting to know about these concepts, eery time when I was doing 3D modeling with global illumination and path tracing enabled I wondered why it took so much time to render a single frame. Now I know why it takes an exceptionally great amount of time to render considering the amount of details captured when global illumination with a high number of bounces are enabled.
Looking through all of these different bounce number renderings of the same picture got me wondering if there was an optimal or standard number of bounces that was normally used or "optimal"
The image becomes brighter when there is more bounces, but it is hard to tell the difference between 8 and 16 bounces, which can be explained as the energy of light decays after bounces and the render recursion converges.
I noticed that as the number of bounces increased, so did the overall brightness of the image. But I could also see that there is some increased noise and a few white artifacts that now appear in this image. Why is that the case? Look near the top lamp for example.
Even though this image aims to replicate the global illumination that we see in real life, I tend to think that this looks less realistic because of artifacts noted in some of the above comments. For example, we see white noise close to everywhere and the whole scene just looks brighter overall.
It seems like it's important to have at least some extra bounces when it comes to global illumination. When we look at certain objects like the lamp or the glass bottles on the tables, it gets rendered correctly when we reach two or four bounces (they were originally just black). However, if we add more bounces, the image just becomes brighter and adding them doesn't seem too necessary.
For efficiency purposes, is the number of bounces constrained to perhaps 1-2? I feel like there are marginal returns on the later bounces of light, and so they can be sacrificed for performance.
Is there a limit to how many bounces the rendering should have? because in real life there seems to be infinite bounces of lights, but for some reason these photos appear to be more faded as the number of bounces increase.
@sueyoungshim I think the Russian roulette for global illumination (that we implement in proj2) could help tackle the issue of the under saturation while providing more information than reducing the number of bounces
@ArjunPalkhade That would mostly depend on whether you need it rendered in realtime or not. Video games tend to be limited to 1-2 bounces or use other methods to approximate this behavior like ambient occlusion. CGI in movies can take as long as needed and can range from 3-10+