POV-Ray : Newsgroups : povray.general : Casting a shadow without an object Server Time
29 Nov 2024 17:57:08 EST (-0500)
  Casting a shadow without an object (Message 1 to 10 of 10)  
From: John D  Gwinner
Subject: Casting a shadow without an object
Date: 19 Jul 2005 13:26:27
Message: <42dd37c3$1@news.povray.org>
I want to do a strange effect with a normal looking person casing a demon 
shadow on the walls as she walks past.

I was thinking one way to do this might be to have a series of dark 
(negative) lights projecting 'through' the object (wings), without the 
object (wings) being rendered.

Any other ideas?

           == John ==


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From: Tim Nikias
Subject: Re: Casting a shadow without an object
Date: 19 Jul 2005 13:50:32
Message: <42dd3d68@news.povray.org>
> I want to do a strange effect with a normal looking person casing a demon
> shadow on the walls as she walks past.
>
> I was thinking one way to do this might be to have a series of dark
> (negative) lights projecting 'through' the object (wings), without the
> object (wings) being rendered.
>
> Any other ideas?

Use no_image and no_reflection on the shadow-casting object. Wouldn't that
suffice?

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: Raf256
Subject: Re: Casting a shadow without an object
Date: 19 Jul 2005 17:10:33
Message: <l340r2-0e8.ln1@raf256.com>
"Tim Nikias" <JUSTTHELOWERCASE:timISNOTnikias(at)gmx.netWARE>
<42dd3d68@news.povray.org> Tuesday 19 of July 2005 19:50

> Use no_image and no_reflection on the shadow-casting object. Wouldn't that
> suffice?

and perhaps also no_rediosity and photons passthrough?

-- 


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From: Tim Nikias
Subject: Re: Casting a shadow without an object
Date: 20 Jul 2005 01:42:49
Message: <42dde459$1@news.povray.org>
> > Use no_image and no_reflection on the shadow-casting object. Wouldn't
that
> > suffice?
>
> and perhaps also no_rediosity and photons passthrough?

With no_image and no_reflection, radiosity won't touch the object anyway,
but you're correct about the photons, they need to pass_through.

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>


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From: John D  Gwinner
Subject: Re: Casting a shadow without an object
Date: 20 Jul 2005 12:24:45
Message: <42de7acd$1@news.povray.org>
Thanks folks, even easier :)

         == John ==


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From: Alain
Subject: Re: Casting a shadow without an object
Date: 20 Jul 2005 13:45:36
Message: <42de8dc0$1@news.povray.org>
John D. Gwinner nous apporta ses lumieres en ce 2005-07-20 12:25:
> Thanks folks, even easier :)
> 
>          == John == 
> 
> 
Don't forget to put no_shadow on the visible object, or you get two shadows.

Alain


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From: Jellby
Subject: Re: Casting a shadow without an object
Date: 21 Jul 2005 10:40:13
Message: <9tn4r2-r5c.ln1@badulaque.unex.es>
Among other things, Alain saw fit to write:

> Don't forget to put no_shadow on the visible object, or you get two
> shadows.

But no_shadow means no highlights either, doesn't it?

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby


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From: Alain
Subject: Re: Casting a shadow without an object
Date: 21 Jul 2005 18:40:23
Message: <42e02457$1@news.povray.org>
Jellby nous apporta ses lumieres en ce 2005-07-21 10:26:
> Among other things, Alain saw fit to write:
> 
> 
>>Don't forget to put no_shadow on the visible object, or you get two
>>shadows.
> 
> 
> But no_shadow means no highlights either, doesn't it?
> 
Not at all. The highlights are a function of the brillance and the specular or phong
in the finish. 
The only thing, is if the subject get self shadowed, it wont'cast shadow on itself. At
the same 
time, the no_image one will cast shadows on the main subject.

Alain


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From: Rune
Subject: Re: Casting a shadow without an object
Date: 21 Jul 2005 21:55:26
Message: <42e0520e$1@news.povray.org>
Alain wrote:
> Jellby nous apporta ses lumieres en ce 2005-07-21 10:26:
>> Among other things, Alain saw fit to write:
>>
>>> Don't forget to put no_shadow on the visible object, or you get
>>> two shadows.
>>
>> But no_shadow means no highlights either, doesn't it?
>>
> Not at all. The highlights are a function of the brillance and the
> specular or phong in the finish. The only thing, is if the subject
> get self shadowed, it wont'cast shadow on itself. At the same time,
> the no_image one will cast shadows on the main subject.

The confusion may come from the fact that using shadowless in light_sources 
does indeed mean no highlights.

Rune
-- 
3D images and anims, include files, tutorials and more:
rune|vision:  http://runevision.com
POV-Ray Ring: http://webring.povray.co.uk


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From: Jellby
Subject: Re: Casting a shadow without an object
Date: 22 Jul 2005 10:40:07
Message: <fja7r2-qd8.ln1@badulaque.unex.es>
Among othor thigs, Rune saw fit to write:

> The confusion may come from the fact that using shadowless in
> light_sources does indeed mean no highlights.

Oh, yes... that was it!

no_shadow -> no shadow
shadowless -> no shadow, no highlights

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby


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