> Radiosity only? I can see a very slight reddish hue on the left side of the
> cubes. Is this from a gradient-colored sky?

Yes, I light things like this quite a lot.  It can be time consuming to
render, and takes a lot of tweaking sometimes, but tends to give some nice
results.

A couple of tips.  Sometimes images lit like this can look very washed out.
Try increasing the brightness of your sky_sphere way above rgb 1,
particularly in the primary light direction, and then reduce the overall
light level using the brighness keyword in the radiosity block.  This will
tend to increase the tonal range of the lighting, but at the expense of
making any reflections look weird - you'll need to tweak things like the
'exponent' of the reflective surfaces to make them look right again.

For example, the sky_sphere I used for the iso-granite-granules image was:

    gradient x
    color_map {
      [0 rgb <5,1,0>]
      [0.2 rgb 1]
      [0.8 rgb 2]
      [1 rgb <7,7,8>]
    }
    scale 2
    translate -x

(rotated as appropriate of course) which required a radiosity brightness of
0.6.

Also you won't get any specular highlights on surfaces as you would do with
direct lighting, but this can be countered by placing a very dim light
(i.e. rgb 0.001 or something) where the primary light would be coming from,
and then using specular values of the order of 1000.  This will give you
specular highlights as a result of the light source even though the diffuse
component is negligible.  Use light groups to make sure no other lights
affect the surface in ways you don't want.

I'm not saying this stuff is 100% brilliant, but I've used it before to get
some reasonable results.  It can be more trouble than its worth.

L
-

Post a reply to this message