> "Reuben Pearse" <reu### [at] pearsecouk> wrote:
>> Hi Sam,
>>
>> Thanks for the comments. I think the Lego models are *too* shiny. I started
>> investigating sub-surface scattering, but didn't really get very far. I
>> tried adding a finish that uses a subsurface setting, but it didn't seem to
>> make any difference. I've probably got the settings wrong. Does SSS work
>> when using HDR lighting?
>>
>> I've uploaded the original version of a render of Qui-Gon Jinn to my
>> website - I'm using POV-Ray v3.7 RC7
>> http://www.pearse.co.uk/lego/models/qui-gonjinn/
>>
>> Perhaps you could take a look at how SSS could be applied?
>>
>> Thanks in advance
>>
>> Reuben
>
> Not sure if SSS is really needed, LEGO figures are pretty hard, solid plastic.
> That said, I agree that they may be a little too shiny, I would approach this by
> toning down the reflectivity.  If you are using Fresnel with ior (which I would
> recommend if you are not), try keeping your ior in the range between 2.0 and
> 3.0.
>
>
> Yoda, or at least the ones I have seen, have a rubber head.  So this would need
> to be quite a bit less shiny and reflective (maybe SSS could help a ltille on
> this one)
>
> -tgq
>

Subsurface scattering is always present for plastics if it's not covered 
by some metallic coating, like chroming.
Here, it should be keep to a low translucency level. Interior with an 
ior is a must for both fresnel reflection and SSLT.

Normaly, subsurface only interact with regular light_source, and only 
the regular finish is used to compute radiosity effects from the objects.

If you use HDR with radiosity to illuminate your scene, or any kind of 
emissive object, you need to add this in the global_settings:

subsurface{radiosity on}

This allow radiosity illumination to affect the subsurface component.


Optionaly, you can also add in the radiosity block: subsurface on

This allow the subsurface to affect nearby object through radiosity.

Both options will increase the rendering time.

Most plastics have iors in the 1.3 to 2 range. Very few have higher ior 
than that. Acrylic have the same ior as typical vegetal oil.




Alain

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