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25 Dec 2024 20:51:57 EST (-0500)
  Compeletely white plane with shadows (Message 1 to 4 of 4)  
From: noam
Subject: Compeletely white plane with shadows
Date: 12 Oct 2013 12:30:01
Message: <web.525977f027cbbf09e71ca80c0@news.povray.org>
I want to render an image that has several objects in it, say a sphere, torus
and a cube. All these objects cast a shadow on a white plane. What I'd like is
for the plane to be completely featureless - that is to say completely white -
except for the shadows cast by the aforementioned objects. Currently, if I set
the ambient property of the plane to 1, the shadows of the objects do not
appear. If I set the ambient property to 0, the plane appears grey and doesn't
display a consistent color, rather a smooth gradient as the plane moves away
from the light source. Is there an easy way to achieve the desired result?


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From: Christian Froeschlin
Subject: Re: Compeletely white plane with shadows
Date: 12 Oct 2013 13:31:16
Message: <52598764@news.povray.org>
If you want a realistic result the solution is to move
the light source further away (or use the parallel keyword).
Of course this also affects the shadows so you may need to
compensate by moving the objects closer to the plane.

A different approach might be to set a high value for
diffuse (even > 1.0) so the entire backplane saturates.
However, if you use soft shadows these will still show
some asymmetry.


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From: Christian Froeschlin
Subject: Re: Compeletely white plane with shadows
Date: 12 Oct 2013 13:40:58
Message: <525989aa$1@news.povray.org>
noam wrote:

> rather a smooth gradient as the plane moves away
> from the light source.

just a minor quibble, the effect is not caused by distance
of plane from light source but by angle of incidence of the
incoming light on the plane surface (although distance can
play a role if you also set fade_power and fade_distance)

Come to think of it, it should be possible to use an aoi pattern
(available in POV-Ray 3.7) to adapt the pigment based on the angle
of incidence to the light source location in such away the effects
cancel each other out.


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From: noam
Subject: Re: Compeletely white plane with shadows
Date: 14 Oct 2013 18:50:00
Message: <web.525c7412447e81e71ca80c0@news.povray.org>
"noam" <nomail@nomail> wrote:
> I want to render an image that has several objects in it, say a sphere, torus
> and a cube. All these objects cast a shadow on a white plane. What I'd like is
> for the plane to be completely featureless - that is to say completely white -
> except for the shadows cast by the aforementioned objects. Currently, if I set
> the ambient property of the plane to 1, the shadows of the objects do not
> appear. If I set the ambient property to 0, the plane appears grey and doesn't
> display a consistent color, rather a smooth gradient as the plane moves away
> from the light source. Is there an easy way to achieve the desired result?
Found the answer. Simply add "brilliance 0" to the finish of the plane.


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