I won't waste my time dissecting everything written in this posting but 
in case there are people here who consider taking this posting as a 
valuable statement i will as an example analyze the first point:

> 
> 1.  The phong model is outdated now.   

It is not clear what is actually meant with "phong model" here but it 
has to be assumed it is the method of calculating specular highlights 
introduced by Phong (this is the only feature related to the name Phong 
that exists in POV-Ray).  Now the above statement is certainly not true 
since this technique is frequently used by artists (and not only in 
POV-Ray of course).

> The next release of pov-ray should
> use physically-based BRDFs, and only keep the phong model around for
> compatability.  

This implies POV-Ray's use of the "phong model" (see above) is more than 
one feature of many that can be used or not used which is not the case. 
  What "physically-based BRDFs" are is not explained and neither why the 
"phong model" and other techniques in POV-Ray are not physically-based.

> Phong makes everything look like plastic, including what we
> have been calling "glass".

This is obviously wrong but even if it wasn't this would not be a very 
valuable statement (like 'using red light makes everything red').

> The difference between pov-ray glass and
> physically-based glass in other packages is STRIKING.

This is pointless without examples (and of course wrong - i have seen 
dozens of very realistic glass renders made with POV-Ray).

> Real glass has a
> fresnel effect, where shallow-angled light reflected from the surface tends
> more towards a perfect mirror.

Ah - a new name: Fresnel.  Last time i checked this was a reserved 
keyword in POV-Ray so there has to be some feature related to Mr. Fresnel...

> This also happens in real life.  My
> suggestion is allow BRDFS for those who need them, and base the
> documentation around the Phong model as usual.

The use of the word 'BRDF' is strange here - the "phong model" (if meant 
as explained above) is a BRDF as well.  Apart from that the idea to 
introduce a new feature ("allow BRDFS" - whatever this should mean) but 
not document it is just ridicuous.

Christoph

-- 
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HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 23 Sep. 2004 _____./\/^>_*_<^\/\.______

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