In article <MPG.199d670bbcc1d94f989687@news.povray.org>,
 HermanS <her### [at] pandorabeinvalid> wrote:

> I'm using Povray mostly to represent mathematically defined objects 
> (images and animations). In many cases I have a lot of trouble to place 
> light sources in an adequate way.
> Is there a method for placing light sources in a rather general way or 
> to use ambient light or radiosity to obtain a first idea of the 
> raytraced objects?

Put this line at the beginning of the scene:

#default {finish {ambient 0 diffuse 1}}

And now put a dim, shadowless light at the camera location. Instead of 
dim, flat, directionless ambient lighting, you are now using a fill 
light. This will help contrast and shading a great deal...without this 
camera light, you can easily end up with areas with no direct lighting, 
and without radiosity they will look very flat. Finally, if I'm trying 
to show off a single object instead of lighting a scene, I generally put 
a bright light to the upper left rear, and a dimmer light either or both 
to the right and behind the object.

For realistic lighting, you need radiosity, which will simulate light 
coming to a point indirectly by bouncing off other surfaces. With 
radiosity, you can reduce or eliminate the fill light. It takes more 
adjustment though, and isn't necessary for a mathematical plot.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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