Hi,

Recently I stumbled over a link to Chris Bartlett's StairCase macro
and downloaded the files.
The first example in StairCaseDoc.pov traced happily in about 7s
with my AMD Athlon 64 3000+ on Windows XP Home SP2.
Because all the examples trace as an animation, I started it with
+kfi0 +kff50 in the command line box and went doing something
else. After a while I checked the progress and noticed that the
tracing was very slow compared to the single trace before.
I quickly checked the messages for the first example and good only
see a difference in the number of objects :
Single trace: 176                Trace time: 7sec
Animation:   168                Trace time: 68sec
Weird, why is there a difference when everything in the file stays the
same?
In order to check every line of the messages I put them beside each
other and found some more differences:

(In the statistics below the first line is the single trace and the second
line is from the animation)

Ray->Shape Intersection       Tests        Succeeded  Percentage
----------------------------------------------------------------
Box                                    506223          120663     23.84
Box                                89402880          221111       0.25
Cone/Cylinder                      21746              3735     17.18
Cone/Cylinder                 25703328             8122       0.03
CSG Intersection                 484477           59250     12.23
CSG Intersection             51406656           76943       0.15
CSG Union                         664369            49209       7.41
CSG Union                     59229408          131033       0.22
Lathe                                  212507            72541     34.14
Lathe                              48054048          155648       0.32
Lathe Bound                       212507          110827     52.15
Lathe Bound                   48054048          195161       0.41
Plane                                  543940          382586     70.34
Plane                                6705216        4650488     69.36
Prism                                1338041          272019     20.33
Prism                              33526080          352735       1.05
Prism Bound                   25342199         2241221      8.84
Prism Bound                  275266864      19341721      7.03
Sphere                                     7470             1798     24.07
Sphere                              4470144              1854       0.04
Clipping Object                   331882          105405     31.76
Clipping Object                   643896          198954     30.90
Bounding Box                   8774139         2655932     30.27
No line !!!
Vista Buffer                      3915348         2326121      59.41
No line !!!

Conclusion: The bounding is off and the Vista Buffers as well.
That explains the statistics and the long trace time.

To be sure I made an ini-file with:

  Bounding=on
  Bounding_Threshold=5
  Draw_Vistas=on
  Light_Buffer=on
  Vista_Buffer=on

in it and traced again. The results don't change, however the
Bounding_Threshold=5  and Draw_Vistas=on were there
in the header, but it didn't work. Vistas in the single trace
works normally.

Can anyone check with some different file if there is something
really wrong with version 3.6.1c.
All my animation files are based on clock values and I never
noticed any differences in trace time with a single trace or in
an animation. However I never used the frame system of POV.
In news.povray.org I can't find any reference to such a behaviour.

I will put the files in povray.binaries.scene-files under
Bug-test-files.

Maybe I do something stupidly wrong, but I don't see it.

Jaap Frank

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