POV-Ray : Newsgroups : povray.binaries.images : Progress on anniversary scene : Re: Progress on anniversary scene Server Time
3 Mar 2024 18:26:13 EST (-0500)
  Re: Progress on anniversary scene  
From: Alain Martel
Date: 11 Feb 2024 10:29:21
Message: <65c8e7d1$1@news.povray.org>
Le 2024-02-10 à 16:35, Cousin Ricky a écrit :
> Of the 4 unfinished elements that were part of my POV-Ray 30th
> anniversary tribute scene, 3 have been published: DeskLamp, RC3Wood, and
> ShapeOfTheDay.
> 
> Unfortunately, there are a couple of lighting problems that showed up in
> the interaction between DeskLamp and ShapeOfTheDay.  Most obviously, the
> caustics are out of control.  More subtly, the light bulb emission is
> too low; this can be seen as the dark spot in the reflection of the lamp
> at the lower right corner of the wood block.  I have not figured out
> what the problems are.
> 
> Image povray_30th_anniversary.20230605.jpg was rendered right after I
> completed RC3Wood, and that is when the caustics bug first manifested.
> This bug has diminished the usefulness of ShapeOfTheDay with refractive
> and, to a lesser extent, metallic objects, but there are workarounds.
> The easiest is to use one of the outdoor settings, which don't use DeskLamp.
> 

In povray_30th_anniversary.20230605.jpg, my guess would be not enough 
photons being shot. If you use a count, I suggest switching to spacing.
When using count, remember that it's spread across all light_source and 
all target objects. ALL non-shadowless light will emit photons unless 
they have this photons block :
photon{refraction off reflection off}
as the default is :
photon{refraction on reflection on}

You may use a non unit value for the target attribute of an object. That 
will be used as a spacing multiplier.
target 0.2 will DIVIDE the spacing by 5 (meaning 25 times more photons), 
while target 2 will double the spacing (meaning 4 times less photons), 
used when shooting photons at that object.

Maybe also increase the jittering of the photons. It looks like there is 
none.

The dark area in the reflection of the desk lamp look credible. I often 
see something similar IRL. You may try to give the interior of the shade 
an finish that include a moderate amount of emission. That should make 
the darker area less obvious.


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