POV-Ray : Newsgroups : povray.text.scene-files : parallel looks_like test scene : Re: parallel looks_like test scene Server Time
24 Feb 2024 18:31:06 EST (-0500)
  Re: parallel looks_like test scene  
From: Mike Horvath
Date: 12 Sep 2016 12:44:46
Message: <57d6db7e$1@news.povray.org>
On 9/12/2016 11:59 AM, clipka wrote:
> And that direction is unchanged: With a parallel light source, the
> direction of all light rays depends only on the /relative/ location of
> two points: The light source's nominal center and the point_at
> parameter. But transformations act on both these points (I've just
> checked the code), so a translation operation changes only the absolute
> location of the points, not their relative location to one another. And
> thus the light direction remains unimpressed.
>
> (BTW, point_at defaults to <0,0,1>.)
>

Crap. I wish I'd known that. Now I have to go back through all my scenes 
and set point_at to <0,0,0>. Might want to mention this in the docs too. 
For instance, you might want to change this:

	Light source default values:
	LIGHT_TYPE        : pointlight
	falloff           : 70
	media_interaction : on
	media_attenuation : off
 >	point_at          : <0,0,0>
	radius            : 70
	tightness         : 10

Mike


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