On Fri, 03 Jul 2015 15:35:51 +0200, clipka <ano### [at] anonymousorg> wrote:

> Am 03.07.2015 um 05:08 schrieb Nekar Xenos:
>
>>>> If you are using fresnel, is it valid (from a PBR point of view) to  
>>>> even
>>>> scale the results using a maximum reflection other than 1?
>>>
>>> Absolutely - if, for instance, your surface is littered with
>>> non-specular material at a microscopic level. Fine rust on iron steel,
>>> for instance, or a thin coating of dust.
>>>
>>> In those cases it might be better, however, to use an average of two
>>> materials.
>>>
>>
>> What about plastic? It reflects, but it's not highly reflective. I don't
>> think I would go higher than 0.5 maximum reflection on plastic.
>
> For plastics - and actually any material that's neither metallic nor  
> coated - I think heavily blurred reflections and a well-chosen ior are  
> the key, not reducing the reflection maximum.
>
> With a high ior, the maximum reflection only occurs when viewing the  
> material almost edge-on. And with blurred reflections, even there the  
> maximum isn't truly achieved, as the effective reflection brightness is  
> tuned down by averaging in reflections at a less shallow effective angle.
>
> BTW, the ior of most plastics is in the range from 1.5 to 1.6.
>

So a shiny plastic has a high ior I assume. Then it makes sense.

-- 
-Nekar Xenos-

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