VraySSS2 - Object Based Illumination Map

[Druski]

Hi,

I have really been enjoying the new VraySSS2 Material shipped with Vray 3.0, especially the new Object-Base Illumination Method, I get much cleaner/accurate results around collision areas and provides a more appealing look in general. It is however, base on my testing, extremely expensive vs the Pre-Pass Illumination map method. It does speed up considerably by decreasing the "Samples Per unit area" parameter, but this is not without a considerable decrease in quality. Does anyone have any other suggestions for how I could optimise the VraySSS2 shader when using this method? Does this method respect the Prepass ID parameter, and would there be any benefit to using an ID of 1 across all objects? I thought about scripting the sample-units per area based on distance to camera, which could work, but have a feeling would lead to a different overall look, perhaps it would not be noticeable.

[vlado]

Does anyone have any other suggestions for how I could optimise the VraySSS2 shader when using this method?

Since the shader needs to calculate the lights (and GI, if "scatter GI" is specified) it might help to make sure that lights themselves render faster (f.e. by reducing their subdivs).

Does this method respect the Prepass ID parameter, and would there be any benefit to using an ID of 1 across all objects?

No, and no.

I thought about scripting the sample-units per area based on distance to camera, which could work, but have a feeling would lead to a different overall look, perhaps it would not be noticeable.

This could work, actually. If the sampling density is not enough, the shader will try to gradually blend to simple diffuse lighting, which for objects that are far away might not be noticeable.

Best regards,
Vlado