Versions affected:
   Pov-Ray v3.1.watcom.win32.r1 (Pentium II optimized)
   Pov-Ray v3.1d.msvc.win32     (Pentium II optimized)

   See attached file for evidence of problem.

   Discription - Observations:
   If renderd as is a visible horizontal defect is seen running through
   each object. The camera position was choosen to get the best angle so
   that the defect was seen in all 6 objects at once. If the y camera
   direction is changed by even a small +/- amount, the position or the
   appearance of the defect changes accordingly.

   There are two different density patterns available for comparison but
   the defect manifests it self equaly in either type used. As such it
   appears that it is not a pattern dependent defect.

   It renders equaly the same in both Pov-Ray versions listed above.

   Verification:
   Before submission this file was sent to Dan Connelly who verified
   that he too observed the problem. It was his opinion, as well as my
   own, that there was a likelyhood that it is a bug and should be
   reported.

   Possible causes are :
   1. Arises from using a lathe object for a media container
   2. Media intereaction - see 3
   3. Proximity of media density patterns to each other
   4. Proximity of lathe objects to each other
   5. Lathe type used - some testing was done using a quadratic spline
      and the defect remained - As the quadratic spline type greatly
      increased the render time it was ommitted from this example to
      increase the speed for testing of the defect.

  Solutions: ?

  My system: Pentium 200 mmx, 512k cache, 128m edo ram, on Win98 platform.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Attachments:
Download 'media_bug_report.pov.txt' (2 KB)