POV-Ray : Newsgroups : povray.general : Shadows and lighting with HDR sky : Re: Shadows and lighting with HDR sky Server Time
27 Nov 2021 19:24:26 EST (-0500)
  Re: Shadows and lighting with HDR sky  
From: Kenneth
Date: 30 Sep 2021 14:15:00
Message: <web.6155fde2c55e1a844cef624e6e066e29@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 29-9-2021 om 07:21 schreef Kenneth:
> >        always_sample on // off by default. I prefer this ON
> >
>
> The Voodoo Master teaches about this (in 2008):
>
> [quote]
> always_sample:
> When set to "off", this effectively sets "nearest_count" to 1 during the
> final render, so that new radiosity samples are only taken if they are
> absolutely needed.
>
> For quick test renders, you may want to set this parameter to "on" to
> get away with a faster pretrace (or none at all).
>
> Otherwise, you will definitely want to set this parameter to "off", as
> new samples taken during final trace may cause visible "jumps" in colour
> or brightness between areas rendered before and after the new sample was
> taken.
>

Yes, I remember reading that. Several months ago, I did some lengthy and
detailed tests with radiosity (which I *hope* to post about soon...), and my own
eyes tell me that the final render looks 'better' with always_sample on.
Specifically, it seems to eliminate some very subtle artifacts that I noticed;
as a simple way of describing the effect, it produced a 'smoother' render
IMO...but hard to describe, unfortunately. However, all of my tests used a
single small rad emitting object in a scene (and no sky_sphere), as I wanted to
try and zero-in on the basic behavior of radiosity and its various settings.

I could be wrong, but it may be that this particular feature of rad has been
improved since Clipka posted that info(?)

Or it could be just my personal preference, ha. As the old saying goes,
"One man's meat is another man's poison" (which may not translate well?)

;-)


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