[Radiance-general] Re: surface normal

[Greg Ward]

Hi Giulio,

You can get the effect you want by using the RdotP variable in a 
BRDTfunc material and applying it to the specular reflection variables. 
  (As you noticed, RdotP is only available for the general reflectance 
types.)

-Greg

> From: Giulio Antonutto <Giulio.Antonutto@arup.com>
> Date: Tue Oct 21, 2003  8:13:31  AM US/Pacific
>
> hi everybody!
> I am playing with textfunc and mixfunc... just to create some changing
> color-normal materials....
> what I would like to do is to change the color according to the 
> perturbated
> normal ...
> to do that I think to use the variable RdotP (perturbated dot 
> product)....
> but radiance doesn't seem to recognize it... (probably it works only 
> with
> brtdf?)
> of course if I use Rdot... the normal is always the same and
> deformation-color are not changing together....
>
> I would like to do something like:
>
> id1 mixfunc id2
> 4 idA idB f(RdotP) .
> 0
> 0
>
> where idA and idB have same deformations but different 
> color-specularity and
> f(RdotP) is a function of Rdot-Perturbated
>
> any idea?
>
> thanks
> giulio