Noisy results with using other shaders in Environment Tag

[antonbohlin]

Hello all,

Don't know if this is a common mistake I'm doing (with an easy fix?) but if I combine my HDRI with for example a Color Correction or Mix shader in my Sky/Environment Tag everything instantly gets much more grainy. I often want to do some color correction on my HDRI or add a bit of color tint to it, but not at the cost of more samples of course (or doing it in Photoshop). Don't really understand why it happens or how to work around it, there's no Sample Rate for example in the Environment Tag or in the Image Texture shader.

Hoping there's an easy solution to this!

Many thanks

[aoktar]

It's a internal thing about renderer. And it's propably how "importance sampling" is handled with complex shaders.

[bepeg4d]

Hi antonbohlin,
adding a shader to the Environment node brakes the Importance sampling effect.
But you can duplicate your HDR Environment node and use the non filtered version as Primary environment, while the copy filtered with any kind of shader in Visibility mode.
Normal HDR Environment:

Filtered Primary Environment mixed with an orange color with falloff node, note that the shadow is lost, due to the absence of Importance sampling:

Filtered Environment in Visibility mode with Backplate option active:

Happy rendering,
ciao beppe

[antonbohlin]

Thanks for the answers!

@beppe Yes I see - I understand that I can use Environments with visibility only, but what I want to achieve is what you have in your second example. To for example mix color into the HDRI and use that as the primary environment. So your second example does break Important Sampling, right? It still looks quite clean and noise free though, but maybe this is because of the example itself and when applied in other situations introduces the noise back again. Or is this some trick that has something to do with the fact that you're using the Falloff shader?

So basically if I want to do introduce some color correction to my primary environment HDRI I have to either do it in Photoshop or crank my samples?

Thanks

[bepeg4d]

A workaround, without leaving c4doctane, is to copy the environment node in a new scene with Panoramic camera at 0,0,0 and save a render in Radiance HDR from the c4d save menu render settings option, then use it as primary environment in the original scene with importance sampling active and everything in the right place:

ciao beppe