>   I am looking for some clarity on what the 'samples' setting actually controls
> for subsurface in global settings.
>
> version 3.7 RC7
>
> The documentation (3.4.6.3.3.4 Subsurface Light Transport) states the setting
> controls "the number of samples for the diffuse scattering and single-scattering
> approximation". What is the difference in diffuse scattering and single
> scattering??
>
> Now according to what I have read on the theory behind subsurface light
> scattering there are so many bounces going on that regardless of the material
> you will always get an isotropic scattering effect. So this would account for
> the diffuse setting. I would assume this would be a similar setting to
> scattering media type 1 and increasing samples will control how evenly light is
> distributed.
>
>   So I am puzzled at what is meant for single scattering and what that setting
> will effect/control.
>
>

Single scattering is for rays that only scatters once in the material. 
Enter, scatter, exit.
A low value for that can create some star shapes around highlights, at 
least, that's what I got in my experiments.

Diffuse scattering is for rays that scatters many times.

The best thing to do, is to make a test scene with only a single simple 
shape, like a plain white sphere, a single light_source and the camera.

Now, play around with the parameters.



Alain

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