POV-Ray : Newsgroups : povray.programming : CSG Bounding box algorithm : Re: CSG Bounding box algorithm Server Time
5 Dec 2021 14:52:06 EST (-0500)
  Re: CSG Bounding box algorithm  
From: omniverse
Date: 25 Aug 2017 08:05:00
Message: <web.59a011df818ca7929c5d6c810@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
> Looks like the b'box computation for quadrics (sorry, not quartics; got
> that wrong in the previous post) fails to respect the `inverse` keyword
> for /some/ reason.

Curiouser and curiouser, I was able to get the correct CSG shape (almost) by
changing the Cylinder_Y to:

 quadric
  {<1, 0, 1>,
   <0, 0.000000001, 0>, // one billionth
   <0, 0, 0>, -1
  }

Not perfect because of a slight xz offset, which can be seen when enclosing it
with semi-transparent cylinders with the same size.

Not only that, this causes Bald Eagle's bounding macro to go wild, reporting the
dimensions to be 10 billion in every direction from <0,0,0>.

Seems like a precision problem, but I wouldn't know so thought I would mention
this here in case it means something.


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