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3 Aug 2024 06:16:09 EDT (-0400)
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From: Francois Labreque
Subject: Re: analyse d'ombrage
Date: 7 Jun 2004 20:24:46
Message: <40c5074e@news.povray.org>
Program ended abnormally on 07/06/2004 10:20, Due to a catastrophic Phil Cook error:
> And lo on Fri, 04 Jun 2004 18:02:46 -0400, Alain <aze### [at] qwertygov> 
> did  spake, saying:
> 
>> Harold nous apporta ses lumieres ainsi en ce 2004/06/04 17:08... :
>>
>>> Babblefish gives us English folks this:
> 
> <snip>
> 
>> Hoo! the /Joys/ of automated translation... Whatever the original and  

>> beleive"  loony toonesk language.
> 
> 
[snip]

> 
> Still didn't get avidemment and still a bit looney-toonesk, but still  
> sense can be discerned a little better than Babblefish's for future  
> reference.
>




-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/*        @        */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/*   videotron.ca  */}camera{orthographic location<6,1.25,-6>look_at a }


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From: ElProfesor
Subject: Re: analyse d'ombrage
Date: 11 Jun 2004 02:40:01
Message: <web.40c952f3fcc530ea265dc100@news.povray.org>
Here is a hand-made translation ;)


--------------------
For the needs of a project I must perform some shading processing with a
ray-tracer. I was led towards POV-Ray, which I am currently looking at.

I wonder to what extent it's possible to build a file with the list of
objects masked by a shadow, so as to process it later.
As an example let's imagine that I cast the shadow of an object onto the
"floor". I would like to know what "elements" are hit by the shadow, and
possibly the density of the latter.

Hoping my request is clear enough, I'm eagerly waiting for any information
regarding the topic.
--------------------


the "eagerly".


Now some suggestions: maybe the trace () function would help, although you
would have to do some sampling across the floor. And that would work only
with point-light sources (btw, the shadow cast by a single point-light
source is uniform and determined by the ambient parameter of the floor).
Basically, you would reimplement the main loop of the ray-tracer, without
the calculations of course. I think the trace () tutorial in POV's help is
just about writing a ray-tracer within POV-Ray.

Placing the camera straight above the floor to get a flat 2D representation
of it, would also help. You could even make the object (see no_image
modifier), leaving only its shadow.


Bonne chance !
TV


"marc bonnamy" <mbo### [at] ausyfr> wrote:

>



>




> l'ombre d'un objet sur le "sol".


>

> information.
>

>
> Marc.


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