POV-Ray : Newsgroups : povray.general : min_ and max_extent of an intersection object : Re: min_ and max_extent of an intersection object Server Time
15 Jul 2024 19:55:28 EDT (-0400)
  Re: min_ and max_extent of an intersection object  
From: Thomas de Groot
Date: 27 Jun 2020 02:38:47
Message: <5ef6e977@news.povray.org>
Op 26/06/2020 om 09:07 schreef Thorsten Froehlich:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> "Note: This is not perfect, in some cases (such as CSG intersections and
>> differences or isosurfaces) the bounding box does not represent the
>> actual dimensions of the object."
>>
>> The hell it doesn't!
>>
>> So, I am left with the good old trial-and-error finding of the right
>> dimensions/locations of intersection objects. Not a big deal afaiac ;-)
>>
>> Still, I have been wondering if there would be other, smart, ways to do
>> the same? And - just out of pure curiosity - why do min_extent and
>> max_extent not work with intersections or differences? Where isosurfaces
>> are concerned, I can imagine indeed...
> 
> LOL, the problem is so much simpler: This is a patch added from the old MegaPOV,
> and all it does is provide access to the internal bounding boxes POV-Ray uses to
> speed up rendering. Of course, a perfect bounding box does not matter as much
> for this purpose, and the bounding in POV-Ray was never well optmised.
> 
> In fact, for CSG is is mostly additive (for the most part the biggest box
> bounding all objects) and for isosurces you do actually provide the bounding box
> via contained_by .
> 
> Thorsten
> 

Ah! yes, I hear a distant bell tolling.

-- 
Thomas


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