POV-Ray : Newsgroups : povray.newusers : Colored shadows Server Time
28 Mar 2024 07:24:37 EDT (-0400)
  Colored shadows (Message 1 to 5 of 5)  
From: Mr
Subject: Colored shadows
Date: 1 Feb 2017 08:50:01
Message: <web.5891e757b222159a16086ed00@news.povray.org>
Hi,
I know this is not a realistic feature.
Is there a way to specify that all shadows cast by one light are colored by some
tint? (I'm not talking of the highlight color, but rather separate tint of the
shadows and on a per light basis.)


Post a reply to this message

From: Alain
Subject: Re: Colored shadows
Date: 1 Feb 2017 16:25:37
Message: <58925251$1@news.povray.org>

> Hi,
> I know this is not a realistic feature.
> Is there a way to specify that all shadows cast by one light are colored by some
> tint? (I'm not talking of the highlight color, but rather separate tint of the
> shadows and on a per light basis.)
>
>

Possible but cumbersome. It involve using projected_through lights 
associated with your base light(s).

It should work as follow:
Declare all the objects that are to have coloured shadows in some large 
unions.
Place that, or those, union in your scene.
Place all of your lights.
Place copies of all the lights that are to cast coloured shadows. Those 
copies have the colour that you want the shadows to have. They also have 
the projected_through attribute using your large union.


shine in areas that would otherwise be in shadow and don't shine in 
areas that would be lighted using a normal light_source.
It works well with area_light and parallel.
Using spot_light is pointless.
In my tests, it don't like photons. You need to set the 
projected_through object as photons{pass_thgough} or it won't produce 
any photons.

It should be interesting using transparent objects as projected_through 
object. Would an object with pigment{rgbf<0,1,0,1>} gives magenta 
illumination?


Alain


Post a reply to this message

From: clipka
Subject: Re: Colored shadows
Date: 2 Feb 2017 07:48:56
Message: <58932ab8$1@news.povray.org>
Am 01.02.2017 um 14:49 schrieb Mr:
> Hi,
> I know this is not a realistic feature.
> Is there a way to specify that all shadows cast by one light are colored by some
> tint? (I'm not talking of the highlight color, but rather separate tint of the
> shadows and on a per light basis.)

Since a shadow by definition is the complete /absence/ of any influence
whatsoever from a specific light source, that's not possible.

However, as Alain mentioned already, POV-Ray's `projected_through`
mechanism /may/ be a useful tool for what you are trying to achieve,
depending on your exact intentions.


Post a reply to this message

From: scott
Subject: Re: Colored shadows
Date: 2 Feb 2017 08:01:42
Message: <58932db6$1@news.povray.org>
> I know this is not a realistic feature.
> Is there a way to specify that all shadows cast by one light are colored by some
> tint? (I'm not talking of the highlight color, but rather separate tint of the
> shadows and on a per light basis.)

You could try replacing your existing light_source with:

light_source{ color shadow_colour shadowless}
light_source{ color (X-shadow_colour) }

Where X is the original colour of your light, and shadow_colour is the 
colour you want your shadows to be illuminated with.

eg:

light_source{<-10,25,-25> color rgb <0.4,0.0,0.0> shadowless}
light_source{<-10,25,-25> color rgb <0.6,1.0,1.0>}

Will give red tinted shadows, but still give white light for bits not in 
shadow.


Post a reply to this message

From: clipka
Subject: Re: Colored shadows
Date: 2 Feb 2017 09:33:51
Message: <5893434f$1@news.povray.org>
Am 02.02.2017 um 14:01 schrieb scott:
>> I know this is not a realistic feature.
>> Is there a way to specify that all shadows cast by one light are
>> colored by some
>> tint? (I'm not talking of the highlight color, but rather separate
>> tint of the
>> shadows and on a per light basis.)
> 
> You could try replacing your existing light_source with:
> 
> light_source{ color shadow_colour shadowless}
> light_source{ color (X-shadow_colour) }
> 
> Where X is the original colour of your light, and shadow_colour is the
> colour you want your shadows to be illuminated with.

Looks legit; smart idea!


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.