"TinCanMan" <Tin### [at] hotmailcom> wrote in
news:3d3af599@news.povray.org 

> 1.4 is quite high for dispersion, realistic values are in the range of
>  1.01 or so.  1.1 can give nice but unrealistic results.  The
> dispersion value is basically the ratio of the ior for red to the ior
> for violet for a given material.   I have an ior include file that has
> iors and dispersion values for a lot of different materials and that
> is essentially how the values look:
> ior = (ior_red+ior_violet)/2
> dispersion = ior_red/ior_violet

I partialy fixed problems - the filter in pigment was too big, and ambient 
was almost ignored. 

But still - why using even dispersion 1.00001 makes objct _much_ brighter - 
so I have to change amient from 0.0 to about 1.0 to have simmilar results 
as with no dispersion


Now I use following material, and it gives nice results

    texture {
      pigment { color rgbf <.93,.98,.999, .98> }
      finish { 
        specular .8 roughness 0.001
        phong 0.2 phong_size 20
        reflection { .03 .11 }
        diffuse .60
        ambient 2
      }
    }  
    interior { 
      ior 1.70 fade_power 1 fade_distance 50
      dispersion 1.2 dispersion_samples QQ_Disp
    }  


-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M

Post a reply to this message