In article <39a476f6@news.povray.org>, "Darth Sylvax" 
<dar### [at] freefr> wrote:

> what are the differences between Pov Ray & BMRT ?

In which areas?

1) POV-Ray is freeware, BMRT is shareware (though free for 
academic/non-commercial use).

2) POV-Ray is officially supported on many platforms, has unofficial 
compiles for many others, and can easily be compiled for most others. 
BMRT is only available for a few platforms.

3) POV-Ray traces mathematical primitives directly, without tesselating 
them into triangles. I could be wrong, but I believe BMRT tesselates 
primitives first. This means you can get "facets" on curved surfaces if 
you don't use enough triangles, and memory consumption is higher.

4) I'm not sure, but I think POV-Ray supports many more primitives than 
BMRT. However, BMRT supports NURBS objects(Non Uniform Rational Bezier 
Spline, a commonly used primitive for organic shapes), which POV does 
not directly support.

5) POV-Ray uses patterns, blend maps, and other texture attributes to 
texture objects. BMRT uses "shaders", which allow the user to program 
the exact method to use for texture calculation, but have a harder 
learning curve. Note: there is a POV patch which adds shaders, but work 
on it is still in progress.

6) Related to the #2 and #5: there are several unofficial compiles 
adding language and rendering features, such as isosurfaces, shaders, 
new patterns, media enhancements, etc. I do not think there are 
equivalents for BMRT.

7) BMRT uses the RenderMan language specification for scenes, including 
shaders, POV has it's own scene description language.

8) BMRT supports displacement mapping, POV does not.(at least, not 
directly)

And various other things...there is a POV version that has photon 
mapping, which as far as I know isn't done by BMRT, etc.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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