POV-Ray : Newsgroups : povray.advanced-users : looks_like (again) : Re: looks_like (again) Server Time
23 Jun 2024 22:48:19 EDT (-0400)
  Re: looks_like (again)  
From: Alain
Date: 10 Mar 2018 19:33:44
Message: <5aa47968$1@news.povray.org>
Le 18-03-10 à 18:56, omniverse a écrit :
> Mike Horvath <mik### [at] gmailcom> wrote:
>> I have the following settings. However, I can't get the sun_object to
>> appear visible. What am I doing wrong? Thanks.
> 
> Well, I think it's a problem with distance.
> 
> If the location is divided by 10 billion, or multiplied by 1e-10 (one ten
> billionth) it will show the sun when a camera at <0,0,0> is set to look_at the
> sun location.
> 
> light_source
> {
>   light_source_location*1e-10
>   rgb 1
>   looks_like
>   {
>    sun_object
>   }
>   parallel
>   point_at <0,0,0>
> }
> 
> camera {
>   location <0,0,0>
>   look_at light_source_location
> }
> 
> 
> 

This happen when the dimensions range become to large. You get hit with 
precision loss.
Try to keep your range of scales to less than 1e6 if at all possible.
If your smallest object is about 1 unit in size, the farthest object 
should be located at less than 1000000 unit away.

If dividing the Sun's location by 1e10 makes the sun_object visible, 
it's obvious that your scale range is WAY to large !
When using a parallel light, you can always safely place it much closer, 
if you also take care to scale it down proportionally.


Alain


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