Bob H. wrote:

> "Daniel Matthews" <lig### [at] bigpondnetau> wrote in message
> news:182### [at] 3-enet...
>> Bob H. wrote:
>> >
>> > A gradient layered texture would do that, somewhat anyway.
>>
>> Have you an example or a URL for such a method?
>> I am still learning to translate into POV. :o)
> 
> // dirt accumulation texture example
> 
> light_source { <0, 100, -50>, 1 }
> 
> camera {
>    location <0, 1, -10>
>    look_at 0
> }
> 
> #declare CSG=
> union{
> difference{
>                 plane {-z,0}
>                 cone {<0,0,-0.1>,5,<0,0,2>,2.5}
>           }
>                 cone {<0,0,2>,2.51,<0,0,0>,0}
>                 texture {
>                 pigment{rgb<1,1,1>}
>                 finish {ambient 0.5 diffuse 0.5 specular 0.1 roughness
>                 0.1} }
>                 texture {
>                 pigment{gradient z turbulence 0.1
>                         color_map {
>                                 [0 color rgbf 1]
>                                 [0.75 color rgbf <0.7,0.67,0.6,1>]
>                                 [0.9 color rgbf <0.7,0.67,0.6,0.75>]
>                                 [1 color rgbf <0.7,0.67,0.6,0.5>]
>                         } scallop_wave scale 4 translate z/4
>                         }
>                 finish {diffuse 0.3 specular 0.05 roughness 0.15}
>                 }
>           }
> 
> object {CSG rotate <0,45,0>}

Thanks I will have a play with that. I gather that any detail that is cut 
to a certain depth exposes a darker part of the pigment, thus emulating 
dirt accumulation in all grooves of sufficient depth.

The problem is that grime deposits are normal variance dependent.
How can I have a texture in POV that is dependent on a calculation 
involving it's normal in relation to surrounding normal values?

Must I use POVMan and a renderman style shader?

Post a reply to this message