Hi there,

I'd like to know if it's possible to make a render like what an "Ambient
Occlusion" pass could give.

See the left part of this picture :
http://news.povray.org/povray.binaries.images/attachment/%3Cweb.48f739123ce46002bd1b3ad10%40news.povray.org%3E/ambiento
cclusiontest.jpg

I'd like to find a way to do that from an already textured and colored scene
which is quite huge. It is only because I like this gray scaled effect.

So if some of you could give me some help, I'd very appreciated it.

Thanks in advance.

Post a reply to this message

> Hi there,
>
> I'd like to know if it's possible to make a render like what an "Ambient
> Occlusion" pass could give.
>
> See the left part of this picture :
>
http://news.povray.org/povray.binaries.images/attachment/%3Cweb.48f739123ce46002bd1b3ad10%40news.povray.org%3E/ambiento
> cclusiontest.jpg
>
> I'd like to find a way to do that from an already textured and colored scene
> which is quite huge. It is only because I like this gray scaled effect.
>
> So if some of you could give me some help, I'd very appreciated it.
>
> Thanks in advance.
>
>
>
>

Usualy, those who do ambient occlusion start with a scene that use only 
white as a pigment.

As ambient occlusion is a kludge approximating a part of what radiosity 
does, and you only want a gray scale image. You can:

- make a copy of your scene.
using search and replace...
- Remove all pigment and replace them with a plain white one, or light gray.
- Do the same to remove all finishes.
- Do a normal radiosity render.

You may add gray_thresshold 1 to force the radiosity to ignore the 
colours effect.

Another option:
Do a radiosity render of your scene and prost process it to convert it 
to gray scale.





Alain

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Alain <aze### [at] qwertyorg> wrote:

>
> Usualy, those who do ambient occlusion start with a scene that use only
> white as a pigment.
>
> As ambient occlusion is a kludge approximating a part of what radiosity
> does, and you only want a gray scale image. You can:
>
> - make a copy of your scene.
> using search and replace...
> - Remove all pigment and replace them with a plain white one, or light gray.
> - Do the same to remove all finishes.
> - Do a normal radiosity render.
>
> You may add gray_thresshold 1 to force the radiosity to ignore the
> colours effect.
>
> Another option:
> Do a radiosity render of your scene and prost process it to convert it
> to gray scale.
>
>
>
>
>
> Alain

Thank you, I did it by changing all my materials to a white pigment without
finishes.
But this was a bit boring to change it manually.
Is there something like a "change all materials to a white pigment" command I
can write in order to avoid manual changing of all the object's material ?

Post a reply to this message

Darats wrote:

> Is there something like a "change all materials to a white pigment" command I
> can write in order to avoid manual changing of all the object's material ?

Not really. The best you could do is to enclose all your texture
statements in an #if (!USE_DEFAULT_TEXTURE) ... #end block and set
the variable to on for plain renders. Something like this might
actually be handy to have built-in, not just for ambient
occlusion but also, e.g., for creating a depth image
based on a gray gradient.

Post a reply to this message

> Not really. The best you could do is to enclose all your texture
> statements in an #if (!USE_DEFAULT_TEXTURE) ... #end block and set
> the variable to on for plain renders. Something like this might
> actually be handy to have built-in, not just for ambient occlusion
> but also, e.g., for creating a depth image based on a gray gradient.
>

   Yes, it would be also very handy for baking lightmaps from existing
scenes not designed for that purpose. Something like #default{} but for
overriding would be great... but I don't know if it would be easy to
implement.

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

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