"jr" <cre### [at] gmailcom> wrote:
>
> How do you fancy "having a go" at turning the "Perfect Mirror" thread into
> a "FAQ" item ?  (or a draft for an added "Tip" based on your observations ?)
>

12/18/25

Sorry for the delay in responding...real-life and holiday chores took over.

Perhaps a combination of FAQ and B.E.'s all-inclusive test-scene idea would be
the best approach to a better understanding of the current photons behavior; I
will try to put together a draft FAQ (or addition to 'photon tips and tricks')
after the New Year...once I get a clear scenario in my head of how best to
approach it.

Meanwhile, I continued testing in v3.8 beta 1-- and came across some
*really* odd behavior of photons interacting with objects (which proved to be
TEMPORARY, I am happy to say.)

Essentially, the parse time for my earlier test scene here wildly increased-- by
about 15X-- when I simply added an additional box object to the scene, on the
left side of my  light_source, and with no photons block in that object (thus
as a photon 'collector', the default behavior.) But such a gigantic parse-time
increase  made no sense whatsoever, and  I spent the better part of *three days*
trying to understand why it was occurring and how to eliminate it, running test
after test. (Adding a photon block with 'collect OFF' solved it..but that should
not have made such a big difference.)

Near the end of this testing process, I decided to shut down v3.8 and run the
scene in v3.7 instead, to compare results: NO odd behavior there, which was a
good sign. So I brought it back to 3.8... and the problem had suddenly
DISAPPEARED! I could not even reproduce it by fiddling with photon settings.

(At some point prior to my v3.7 test, I *might* have shut down my computer--
which I do on occasion, when I know I will be away from it for hours..but I
don't remember if or when.)  So did shutting it down 'fix' something in the
Windows registry? And/or did running 3.7 correct some temporary glitch in the
3.8 code? Or did Microsoft sneak-in a 'silent' Windows update while I wasn't
looking, breaking (OR fixing) something?

Or was it just 'gremlins and goblins' playing with me?? I think that's the
likely answer.  :-o

So my new and painfully-learned philosophy concerning the current 3.8 betas (1,
and most likely 2 as well) is this:

When unexpected  and unexplainable scene behavior suddenly occurs that makes no
sense, first RESTART the computer (or just POV-ray?) and test again!

Now that all is well, I continue testing photons...   :-)

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