POV-Ray : Newsgroups : povray.general : Disable radiosity render stages? Server Time: 27 Jun 2019 04:54:40 GMT
  Disable radiosity render stages? (Message 1 to 9 of 9)  
From: Mike Horvath
Subject: Disable radiosity render stages?
Date: 12 Jun 2019 02:36:43
Message: <5d00653b$1@news.povray.org>
When radiosity is enabled, there are multiple passes in a render, with 
each pass rendering smaller and smaller boxes until it reaches 1x1 pixels.

Can this be disabled so that I can go straight to the final pass?

Thanks


Michael


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From: JimT
Subject: Re: Disable radiosity render stages?
Date: 12 Jun 2019 12:50:00
Message: <web.5d00f4c6d8e71a88be7517870@news.povray.org>
Mike Horvath <mik### [at] gmailcom> wrote:
> When radiosity is enabled, there are multiple passes in a render, with
> each pass rendering smaller and smaller boxes until it reaches 1x1 pixels.
>
> Can this be disabled so that I can go straight to the final pass?
>
> Thanks
>
>
> Michael

I think not. The implementation of radiosity is iterative, the coarse passes
providing surface colours in the scene to allow the next approximation to give a
better stab at self illumination.

However, there are those who know far more about about radiosity than I.

Thanks,

JimT.


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From: Alain
Subject: Re: Disable radiosity render stages?
Date: 12 Jun 2019 17:46:11
Message: <5d013a63$1@news.povray.org>
Le 19-06-11 à 22:36, Mike Horvath a écrit :
> When radiosity is enabled, there are multiple passes in a render, with 
> each pass rendering smaller and smaller boxes until it reaches 1x1 pixels.
> 
> Can this be disabled so that I can go straight to the final pass?
> 
> Thanks
> 
> 
> Michael

You don't want to do that unless you are loading radiosity data saved 
from an earlier render. In that case, use pretrace_start 1 pretrace_end 
1 in the radiosity block of the global_settings.

If using UberPOV, you can use no_cache in the radiosity block. The image 
WILL look somewhat grainy and the render will take more time.

The other option is to fiddle with pretrace_start and pretrace_end.
If you set both to 1, you'll only get a full frame block before the 
final render pass. This will result in an image of uneven quality and 
probably splotchy.

Normally, it don't reaches 1x1 pixel during the pretrace steps.
The pretrace is used to collect radiosity samples over the whole scene. 
Otherwise, the rendering of the first pixels will only benefit from a 
very restricted set of radiosity data, while pixels rendered later will 
benefit from the data collected by the early parts. The result is an 
image with a mixture of low quality sampling and high quality sampling.

The defaults are :
pretrace_start 0.08
pretrace_end 0.04

For good quality/final renders, you should reduce pretrace_end. Good 
values are in the 0.01 down to 0.0025 range. You can also reduce 
pretrace_start down to 0.02 in those cases.


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From: Anthony D  Baye
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 05:50:00
Message: <web.5d01e320d8e71a88fd6b6fe10@news.povray.org>
Alain <kua### [at] videotronca> wrote:
> Le 19-06-11 à 22:36, Mike Horvath a écrit :
> > When radiosity is enabled, there are multiple passes in a render, with
> > each pass rendering smaller and smaller boxes until it reaches 1x1 pixels.
> >
> > Can this be disabled so that I can go straight to the final pass?
> >
> > Thanks
> >
> >
> > Michael
>
> You don't want to do that unless you are loading radiosity data saved
> from an earlier render. In that case, use pretrace_start 1 pretrace_end
> 1 in the radiosity block of the global_settings.
>
> If using UberPOV, you can use no_cache in the radiosity block. The image
> WILL look somewhat grainy and the render will take more time.
>
> The other option is to fiddle with pretrace_start and pretrace_end.
> If you set both to 1, you'll only get a full frame block before the
> final render pass. This will result in an image of uneven quality and
> probably splotchy.
>
> Normally, it don't reaches 1x1 pixel during the pretrace steps.
> The pretrace is used to collect radiosity samples over the whole scene.
> Otherwise, the rendering of the first pixels will only benefit from a
> very restricted set of radiosity data, while pixels rendered later will
> benefit from the data collected by the early parts. The result is an
> image with a mixture of low quality sampling and high quality sampling.
>
> The defaults are :
> pretrace_start 0.08
> pretrace_end 0.04
>
> For good quality/final renders, you should reduce pretrace_end. Good
> values are in the 0.01 down to 0.0025 range. You can also reduce
> pretrace_start down to 0.02 in those cases.

What you can do, is disable what is called the "Vain Pretrace".  Then the
radiosity passes will only do a luminosity map (I think that's what it's called)
and skip the expensive color passes which have no effect on the final result.

To do this, you can add -RVP to your command line.

Regards,
A.D.B.


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From: Thomas de Groot
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 06:54:25
Message: <5d01f321$1@news.povray.org>
On 13-6-2019 7:46, Anthony D. Baye wrote:
> To do this, you can add -RVP to your command line.
> 

Sorry, where is this described in the docs? RVP is not mentioned anywhere...

-- 
Thomas


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From: Jim Holsenback
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 09:47:46
Message: <5d021bc2$1@news.povray.org>
On 6/13/19 2:54 AM, Thomas de Groot wrote:
> On 13-6-2019 7:46, Anthony D. Baye wrote:
>> To do this, you can add -RVP to your command line.
>>
> 
> Sorry, where is this described in the docs? RVP is not mentioned 
> anywhere...
> 
http://wiki.povray.org/content/Reference:Tracing_Options#Radiosity_Vain_Pretrace


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From: Thomas de Groot
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 10:53:02
Message: <5d022b0e$1@news.povray.org>
On 13-6-2019 11:47, Jim Holsenback wrote:
> On 6/13/19 2:54 AM, Thomas de Groot wrote:
>> On 13-6-2019 7:46, Anthony D. Baye wrote:
>>> To do this, you can add -RVP to your command line.
>>>
>>
>> Sorry, where is this described in the docs? RVP is not mentioned 
>> anywhere...
>>
> http://wiki.povray.org/content/Reference:Tracing_Options#Radiosity_Vain_Pretrace 
> 

My heartfelt thanks! I had been looking for +RVP but forgot to look at 
the web docs in the process.

-- 
Thomas


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From: Alain
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 15:27:49
Message: <5d026b75$1@news.povray.org>
Le 19-06-13 à 01:46, Anthony D. Baye a écrit :

> 
> What you can do, is disable what is called the "Vain Pretrace".  Then the
> radiosity passes will only do a luminosity map (I think that's what it's called)
> and skip the expensive color passes which have no effect on the final result.
> 
> To do this, you can add -RVP to your command line.
> 
> Regards,
> A.D.B.
> 
> 
> 

This don't disable the pretrace step, but it make it somewhat faster.


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From: Anthony D  Baye
Subject: Re: Disable radiosity render stages?
Date: 13 Jun 2019 19:35:00
Message: <web.5d02a4c0d8e71a88fd6b6fe10@news.povray.org>
Alain <kua### [at] videotronca> wrote:
> Le 19-06-13 à 01:46, Anthony D. Baye a écrit :
>
> >
> > What you can do, is disable what is called the "Vain Pretrace".  Then the
> > radiosity passes will only do a luminosity map (I think that's what it's called)
> > and skip the expensive color passes which have no effect on the final result.
> >
> > To do this, you can add -RVP to your command line.
> >
> > Regards,
> > A.D.B.
> >
> >
> >
>
> This don't disable the pretrace step, but it make it somewhat faster.

The odd thing was that it wasn't disabled by default when using -D (No display)

I don't know if this has changed or not, but I brought it up a while ago.

Regards,
A.D.B.


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