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MathGroup Archive 1998

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Re: LightSources

  • To: mathgroup at smc.vnet.net
  • Subject: [mg14469] Re: LightSources
  • From: Martin Kraus <mkraus at theorie3.physik.uni-erlangen.de>
  • Date: Fri, 23 Oct 1998 20:58:47 -0400
  • Organization: Regionales Rechenzentrum Erlangen, Germany
  • References: <70k4fe$en1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Maarten.vanderBurgt at icos.be wrote:
> 
> Hello,
> 
> In the MathGroup archives I found two messages with some questions
> regarding light sources. I attach them below. I did not find any
> answers or responses to them. Currently I have the same questions as in
> these two messages. I did read section 2.9.12 in the book and related
> help items. But this does
>  not answer all these questions.
> Is there anyone who knows more about this or who can point me to the
> right sources?
> 
> thanks
> 
> Maarten van der Burgt
> 
> Icos Vision Systems
> Leuven
> Belgium
> 

Actually I am the author of one of these messages and got a response
from 
Wolfram (I do not have an e-mail address of the developer) about this,
which essentially states that the calculation of  shadings is wrong in
Mathematica, but very difficult to fix.  As the bug is know, it might
be fixed in the next version of Mathematica.
(Therefore I decided to calculate the shading in my applet
LiveGraphics3D as 
documented in the Mathematica book.) 

If you succeed to simulate the wrong calculations of Mathematica, please
let me 
know! I wasted some time on this without success. My basic result was
that there is 
probably more wrong than only a unnormalized view point vector.

Good luck anyway!

Martin Kraus


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