[Radiance-general] gloss specifications to roughness/specularity

[Gregory J. Ward]

Hi Jack,

I know of no way to take standard gloss measurements and convert them  
into something that is physically meaningful, since they combine  
specularity with roughness to obtain a single value at a specific angle.

-Greg

> From: Jack de Valpine <jedev at visarc.com>
> Date: February 6, 2006 8:49:29 AM PST
>
> Hi All,
>
> I am curious if there is a way to estimate material roughness/ 
> specularity based on gloss specifications. PPG provides a gloss  
> range for its factory applied metal coatings (such as DURANAR). The  
> way they indicate this is as a range at a given measurement angle,  
> for example:
> 25% to 35%  at 60 degrees
> This is according to the ASTM-D523 - Specular Gloss.
>
> Is there some way to make this meaningful as a part of a radiance  
> material specification?
>
> Thanks,
>
> -Jack