[ REQ 5028]: bugs in geomview

[stieneck at uran.informatik.uni-bonn.de]

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Dear Ladies and Gentlemen,

may I short introduce myself:
I am Juergen Stienecke and I am taking my diploma examination in computer science at the Rheinische Friedrich-Wilhelms-Universitaet Bonn in Germany.
I am converting 3-dimensionalgeological data.
For testing I sometimes use your package GEOMVIEW to display data on a SUN.
The program QHULL gave me a good suggestion for determing the convex hull for my triangular webs.

(I)
Because I also compute the bounding boxes, I noticed, that sometimes my ones differed from Geomview's.
After cheking my calculations, I could see, that Geomview's bounding boxes were sometimes too small.
So I looked for a single triangle with a wrong bounding box:
{ SKEL 3 1
22 166 -245 
-83 215 -123 
14 162 -61 
4 0 1 2 0 0.0 0.0 0.0 1}

(II)
The other bug, I noticed, appears when regarding a closed triangular web (i.e. every triangle has exact three neighbors).
Sometimes the back triangles are shining through the triangles in the front.
I suppose, you are selecting the triangles to show by the angle, the spectator is looking on.
I realized, that a triangle behind another is yet shown, when it is "very more vertical" than the front one.
An example I attach to this mail.
It is created by the command 'rbox 6 | qhull G >geomview_bug' as you can read in its first line.

I hope this will help you to find the bugs

Greetings

Juergen Stienecke

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Breite Str. 31			Sielsdorfer Str. 11
53111 Bonn			50935 Koeln
(0228) 632469			(0221 )437719
stieneck at uran.informatik.uni-bonn.de
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{appearance {+edge -evert linewidth 2} LIST # rbox 6 | qhull G
{ OFF 3 1 1 # f1
  0.4109   0.1833  -0.1473 
  0.3515  -0.3137   0.2032 
 -0.3853   0.1182   0.1467 
3 0 1 2   0.6266   0.7686   0.9023 1.0 }
{ OFF 3 1 1 # f4
  0.2705 -0.01238  -0.4184 
  0.3515  -0.3137   0.2032 
  0.4109   0.1833  -0.1473 
3 0 1 2   0.9593   0.3525   0.3686 1.0 }
{ OFF 3 1 1 # f5
  0.2808  0.06584  -0.2991 
  0.4109   0.1833  -0.1473 
 -0.3853   0.1182   0.1467 
3 0 1 2   0.3805   0.9282   0.2711 1.0 }
{ OFF 3 1 1 # f6
  0.2705 -0.01238  -0.4184 
  0.2808  0.06584  -0.2991 
 -0.3853   0.1182   0.1467 
3 0 1 2   0.3614   0.9072   0.2451 1.0 }
{ OFF 3 1 1 # f7
  0.2808  0.06584  -0.2991 
  0.2705 -0.01238  -0.4184 
  0.4109   0.1833  -0.1473 
3 0 1 2    0.436   0.9172    0.232 1.0 }
{ OFF 3 1 1 # f8
  0.3515  -0.3137   0.2032 
-0.08714 -0.09114  0.02967 
 -0.3853   0.1182   0.1467 
3 0 1 2   0.2467  0.08152   0.6035 1.0 }
{ OFF 3 1 1 # f9
-0.08714 -0.09114  0.02967 
  0.2705 -0.01238  -0.4184 
 -0.3853   0.1182   0.1467 
3 0 1 2    0.196   0.2293   0.2097 1.0 }
{ OFF 3 1 1 # f10
  0.2705 -0.01238  -0.4184 
-0.08714 -0.09114  0.02967 
  0.3515  -0.3137   0.2032 
3 0 1 2   0.3544  0.06241   0.3068 1.0 }
}