POV-Ray : Newsgroups : povray.binaries.images : AABB reduction by Singular Value Decomposition : Re: AABB reduction by Singular Value Decomposition Server Time
15 Jul 2024 08:25:49 EDT (-0400)
  Re: AABB reduction by Singular Value Decomposition  
From: Bald Eagle
Date: 7 Apr 2021 18:50:00
Message: <web.606e36b7d8cfb0ef1f9dae3025979125@news.povray.org>
"Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:

> Sorry: Not "bounding box minimization", but "minimum volume bounding ellipsoid"

Actually, it IS the bounding box we're minimizing.   The ellipsoid is just the
simplest anisotropic primitive to generate the surface point cloud from, and it
also comports with the dozens of SVD illustrations online.

Convex hulls and bounding ellipsoids are something I have yet to embark on.

I spent far too long converting a FORTRAN90 subroutine for calculating SVD into
SDL - which was tricky, given it has a GOTO statement that jumps BACK in the
The dozen other GOTOs were pretty straightforward once I saw what I had to do.

I hacked the heck out of it and got it to run with no errors, and spit out some
matrices, but I don't get any useful results from it.  I'm sure I botched
something in my marathon editing session, so I have to track down where THIS has
gone off the rails.

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