"Dre" <and### [at] gmailcom> wrote:
> Hi all, I have been struggling bigtime trying to get a realistic plastic
> texture to work with a hdr background.
>
> Whenever I get close it allways looks washed out or way too reflective (ie
> like shiney metal), I'd really like a brilliant white shiney surface.  For
> example the same as a brand new white painted car panel.
>
> If someone could help me out I would much appreciate it!
>
> An quick mock up of my scene is below:
>
> // ----------- code start
> #include "colors.inc"
> #include "textures.inc"
>
> camera {
>   location <0, 0, 10>
>   look_at <0, 0, 0>
>   right x * image_width / image_height
> }
>
> sphere {
>   0, 12000
>   hollow
>   pigment { image_map { hdr "Factory_Catwalk_2k.hdr" map_type 1 } }
>   finish { diffuse 0 ambient 1 }
> }
>
> sphere {
>   0, 3
>   pigment { color rgb 1 }
>   finish { specular 1 roughness 0.0001 reflection 0.13 }
> }
> // ----------- code end
>
> Thanks!
>
> Cheers Dre

first you typically want to explicitly set your diffuse and ambient values
(ambient 0).  For diffuse, I find values from 0.4 to 0.6 usually adequate.

The next step is managing the reflectivity.  I find it is always best to revert
to fresnel reflection.  With this you need to set an ior value, for this I will
typically use from 1.15 to 1.3 depending on how shiny I would like it.

The specular part is optional, as you are using true reflections, but sometimes
it does help a little.  But keep it low and adjust the roughness value for the
'diffuseness' you would like.

sample plastic:

material{
  texture{
    pigment{rgb <1,0,0>}
    finish{
      conserve_energy
      diffuse 0.6
      ambient 0
      specular 0.5
      roughness 0.05
      reflection{0 1 fresnel on metallic 0}
    }
  }
  interior{ior 1.16}
}

With material such as this, especially when used with an HDR environment map,
the most important part is how they reflect the background.  For plastic, you
want to make sure that less bright areas of the background don't reflect much,
but that bright highlights do.


-tgq

Post a reply to this message