POV-Ray : Newsgroups : povray.general : Shadows and lighting with HDR sky Server Time
27 Nov 2021 18:37:43 EST (-0500)
  Shadows and lighting with HDR sky (Message 11 to 11 of 11)  
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From: Thomas de Groot
Subject: Re: Shadows and lighting with HDR sky
Date: 1 Oct 2021 04:32:31
Message: <6156c79f$1@news.povray.org>
Op 30-9-2021 om 20:11 schreef Kenneth:
> 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?)
> 
> ;-)
> 

You might well be right. While posting my Clipka comment, I realised 
that he was writing at a time when version 3.7 was still in a 
development mode. I would be curious to have his updated view on this, 
in particular for version 3.8.

-- 
Thomas


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