|
![](/i/fill.gif) |
Am 11.04.2010 16:34, schrieb Tek:
> I get it in both Megapov 1.21& Povray 3.6. I might try moving over to 3.7
> but my scene's probably using a couple of megapov features.
Um, sorry... I'm so focused on POV-Ray 3.7 that it didn't even cross my
mind that you may still be using 3.6. >_<
>> What is strange, is the fact that the artefacts are of the complementary
>> colour.
>
> It's as if it's using negative lighting values.
It is indeed! Thanks for pointing me in the right direction, that did
ring a bell:
At each radiosity sample location, POV-Ray 3.6 does not only compute the
total incoming diffuse illumination, but also tries to guesstimate the
illumination /gradient/ at that point.
I had always been suspicious of that mechanism's implementation, though
I never managed to demonstrate its bogosity with a sample scene. On the
other hand I couldn't make out any noticeable benefits either, so I
decided to disable it in POV-Ray 3.7, if only to save memory and
processing time.
To verify this theory, I just threw together a patched 3.7.0.beta.36
with the "gradient code" re-enabled, and it did indeed show the very
same complementary-color halos (current official 3.7 betas don't, as
already mentioned in this thread).
Patching POV-Ray 3.6 (or MegaPOV, for that matter) to fix this issue
should be pretty easy: In radiosity.cpp, just delete (or comment out)
the line reading:
#define RAD_GRADIENT 1
That should be all that's needed.
Post a reply to this message
|
![](/i/fill.gif) |