In article <3dd0d8c1@news.povray.org>, "Hugo" <hua### [at] post3teledk> 
wrote:

> > The page is about anisotropic reflections.
> > I got the impression from message
> > that it was about scattering media.
> 
> Sorry I don't know the difference.
> I'm constantly learning... :o)

To be fair, both things are "scattering". The current version of POV 
just only uses that term in relation to scattering media, so that is the 
first thing that people here are going to think of.

Volumetric scattering:
Smoke or sun beams, POV media.

Subsurface scattering:
Things like translucent marble, a kind of volumetric scattering. You can 
do it in POV using media, but there are specialized algorithms that are 
faster, but aren't implemented in POV.

Surface scattering:
Any light bouncing off a surface, including reflections and shading as 
the direction of light becomes more parallel to the surface. In POV and 
most other renderers, specular reflection (like mirrors) and diffuse 
reflection (shading) are separate, diffuse is approximated with a simple 
function of the angle of the normal to the light source, and specular 
reflection by tracing a ray. That page is probably about techniques for 
controlling this kind of scattering. Anisotropic means it is dependant 
on direction as opposed to isotropic where it is the same independant of 
direction, like a brushed aluminum ball compared to a polished chrome 
one. POV can simulate most of this kind of thing with average textures.

-- 
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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