POV-Ray : Newsgroups : povray.programming : CSG Bounding box algorithm : Re: CSG Bounding box algorithm Server Time
28 Nov 2021 21:08:25 EST (-0500)
  Re: CSG Bounding box algorithm  
From: clipka
Date: 24 Aug 2017 04:48:26
Message: <599e92da@news.povray.org>
Am 24.08.2017 um 03:04 schrieb omniverse:

> I was wondering about this after coming across something about the automatic
> bounding from the version 3.5 sample scene chess2.pov while rendering some of
> those old files.
...
> According to what is said here, I suppose that particular CSG object must be a
> problem due to the intersecting planes and quartics (infinite shapes).

Thanks for spotting this one.

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.

> And
> curiously, for me anyhow, is that the deformation changes depending on
> orientation or camera view.

Bounding boxes have that effect. Essentially your shape gets clipped in
"image space" by the outline of the b'box, which changes shape as the
b'box is viewed from different angles: Head-on it's a rectangle, while
at other angles it changes into an irregular hexagon.


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