POV-Ray : Newsgroups : povray.advanced-users : About Crevice Grime - Feature Request Server Time
13 Jun 2024 05:48:46 EDT (-0400)
  About Crevice Grime - Feature Request (Message 1 to 3 of 3)  
From: Edouard
Subject: About Crevice Grime - Feature Request
Date: 13 Mar 2011 17:15:01
Message: <web.4d7d32d6f7de3da4cdaada170@news.povray.org>
I'd thought about this a long time ago when I was writing my proximity pattern
code: programs like Meshlab can colour polygons based on lots of functions,
including ambient occlusion.

What What POV is missing (as far as I'm aware) is the ability to extract the
colour of a polygon and use it as a pigment. If I have a model that has each
polygon with a grayscale value based on something like AO, I'd like to be able
to use that gray value in a pigment_pattern to drive POV's more sophisticated
pigment code (grime in crevices, damage on exposed edges etc).

Does that make sense? Have I explained it clearly?


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From: clipka
Subject: Re: About Crevice Grime - Feature Request
Date: 14 Mar 2011 02:38:15
Message: <4d7db7d7$1@news.povray.org>
Am 13.03.2011 22:10, schrieb Edouard:
> I'd thought about this a long time ago when I was writing my proximity pattern
> code: programs like Meshlab can colour polygons based on lots of functions,
> including ambient occlusion.
>
> What What POV is missing (as far as I'm aware) is the ability to extract the
> colour of a polygon and use it as a pigment. If I have a model that has each
> polygon with a grayscale value based on something like AO, I'd like to be able
> to use that gray value in a pigment_pattern to drive POV's more sophisticated
> pigment code (grime in crevices, damage on exposed edges etc).
>
> Does that make sense? Have I explained it clearly?

If I understand your request correctly, that feature already exists: It 
is called "mesh camera". It will still require two render passes, but 
should do what you want.

Note however that this is a limited solution, as it can be used for mesh 
objects only.


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From: Jaime Vives Piqueres
Subject: Re: About Crevice Grime - Feature Request
Date: 14 Mar 2011 06:31:31
Message: <4d7dee83$1@news.povray.org>

> If I understand your request correctly, that feature already exists: It
> is called "mesh camera". It will still require two render passes, but
> should do what you want.

   Yes, indeed... the mesh texture can be easily baked as a grayscale 
image, which can be used then in several ways with POV-Ray textures. I 
did some tests with "pseudo-AO" which were interrupted by Real Life:

http://www.ignorancia.org/uploads/tools-and-objects/mesh_camera/baking_demo_ao_bronze-verdi.jpg
http://www.ignorancia.org/uploads/tools-and-objects/mesh_camera/baking_demo_ao_marble-verdi.jpg
http://www.ignorancia.org/uploads/tools-and-objects/mesh_camera/baking_demo_ao_copper.jpg


> Note however that this is a limited solution, as it can be used for mesh
> objects only.

   Which is just what Edouard requested... :)

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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