POV-Ray : Newsgroups : povray.binaries.images : Glass for v3.8 finish features Server Time
2 Dec 2022 12:19:16 EST (-0500)
  Glass for v3.8 finish features (Message 11 to 14 of 14)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Thomas de Groot
Subject: Re: Glass for v3.8 finish features
Date: 10 Aug 2022 04:27:15
Message: <62f36be3$1@news.povray.org>
Op 9-8-2022 om 17:18 schreef Chris R:
> This is why I love working with POV and this community.  There's always someone
> who has thought about the same problems and is willing to share their experience
> (and code!)
> 

I uploaded my scene file in p.b.scene-files (same subject line).

Enjoy!

-- 
Thomas


Post a reply to this message

From: Alain Martel
Subject: Re: Glass for v3.8 finish features
Date: 10 Aug 2022 11:42:41
Message: <62f3d1f1$1@news.povray.org>
Le 2022-08-09 à 10:50, Thomas de Groot a écrit :
> Op 9-8-2022 om 14:53 schreef Thomas de Groot:
>> initially, I wanted to concentrate on the hdr light sources though...
>>
> ...and when I do, no photons are generated!
> 
> I use
>    photons {
>      refraction on
>      reflection on
>    }
> 
> for the sphere with the hdr map, identical to the code for the light 
> source. Decreasing spacing down to a ridiculously small value doesn't 
> change anything. I must be missing something here...
> 

The HDR map never emit photons.
What you can do to get caustics from an HDR map is to use radiosity. As 
the surface receiving the caustics is close to the objects causing it, 
your radiosity settings can still be lenient. You only a small 
error_bound value.

Try this as a starter :

global_settings{ assumed_gamma 1
	radiosity{
		error_bound 0.1 // may try smaller
		count 150 1111
		low_error_factor 0.2
		pretrace_end 0.005
		}
	}


Post a reply to this message

From: Alain Martel
Subject: Re: Glass for v3.8 finish features
Date: 10 Aug 2022 11:45:14
Message: <62f3d28a@news.povray.org>
Le 2022-08-09 à 08:43, Thomas de Groot a écrit :
> Op 9-8-2022 om 11:40 schreef Mr:
>> Was it slow to render ? There seems to be no anti aliasing.
>>
> I used +a0.3 +am2 +bm2 +bs8  maybe not the best aa setting but I was 
> playing ;-)
> 
> I think total render time was about 2 hours or a bit more.
> 

Just using +a0.1 instead of +0.3 should improve the result and should 
not increase the rendering time to much.


Post a reply to this message

From: Thomas de Groot
Subject: Re: Glass for v3.8 finish features
Date: 11 Aug 2022 11:25:34
Message: <62f51f6e@news.povray.org>
Op 10-8-2022 om 17:42 schreef Alain Martel:
> The HDR map never emit photons.
> What you can do to get caustics from an HDR map is to use radiosity. As 
> the surface receiving the caustics is close to the objects causing it, 
> your radiosity settings can still be lenient. You only a small 
> error_bound value.
> 
> Try this as a starter :
> 
> global_settings{ assumed_gamma 1
>      radiosity{
>          error_bound 0.1 // may try smaller
>          count 150 1111
>          low_error_factor 0.2
>          pretrace_end 0.005
>          }
>      }

Excellent suggestion, concentrating on the caustics! Thanks Alain. This 
is the result with:

error_bound      0.01
low_error_factor 0.1
pretrace_start  8/max(image_width,image_height)
pretrace_end    1/max(image_width,image_height)

and stochastic render:

+am3 +a0.01 +ac0.90 +r3

render time was only about 10 minutes.
-- 
Thomas


Post a reply to this message


Attachments:
Download 'glass_test_04.png' (554 KB)

Preview of image 'glass_test_04.png'
glass_test_04.png


 

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.