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Re: Problem with evaluating Graphics3D output

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90957] Re: Problem with evaluating Graphics3D output
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Thu, 31 Jul 2008 06:04:23 -0400 (EDT)
  • Organization: The Open University, Milton Keynes, UK
  • References: <g6rnsa$7jr$1@smc.vnet.net>

Cca wrote:

> Here is a problem I discovered right now. First, evaluate
> 
> Graphics3D[{FaceForm[{GrayLevel[0]}, {GrayLevel[0]}], 
>   Cylinder[{{-0.5, 0, 0}, {0.5, 0, 0}}, 0.05]}]
> 
> Now, evaluate the output. My problem: FaceForm is not preserved. Why? Confirming:
> 
> %[[1]]
> 
> How can I preserve FaceForm upon reevaluation?
> 
> This does not happen with
> 
> Graphics3D[{GrayLevel[0], 
>   Cylinder[{{-0.5, 0, 0}, {0.5, 0, 0}}, 0.05]}]

You may have found a bug. I could reproduce the issue on my Mac OS X 
6.0.3 system. Apparently the problem appears with GrayLevel only. I 
tried several variations of your expression (color scheme and geometric 
object) and FaceForm was preserved upon evaluation of the output cell. 
For instance,


     Graphics3D[{FaceForm[Yellow, Blue],
       Cylinder[{{-0.5, 0, 0}, {0.5, 0, 0}}, 0.05]}]

     [ Evaluate the output cell with shift + enter]

     %[[1]]

     {FaceForm[RGBColor[1, 1, 0], RGBColor[0, 0, 1]],
      Cylinder[{{-0.5, 0, 0}, {0.5, 0, 0}}, 0.05]}

Regards,
-- Jean-Marc


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