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 14:11:48 EDT (-0400)
  Re: min_ and max_extent of an intersection object  
From: Bald Eagle
Date: 26 Jun 2020 06:55:01
Message: <web.5ef5d332a1439498fb0b41570@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> I should have known of course, and instead of swearing by Eagle the
> Bald, sacrificing nameless things to the Clipka idol and invoking the
> good spirit of Saint William of the Pokorny (in that order) for a couple
> of days, I should have opened the Grimoire and read:

..oO(Oh boy, he's swearing again...)

> "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!

Well, yes, we all knew that - which is what jr's bounding macro - using trace ()
- is all about, and my attempt at doing the same using SVD were all about.
I had a bit of a hard time visualizing some of what the docs were saying a while
back, and clipka gave a little more explanation about about certain pathological
cases. (presumably he was not referring to you at the time)

If your human/mathematical knowledge lets you know approximately the range of a
function in an isosurface, but you don't know _exactly_the bounds of the
surface, you can iterate through the function with a nested x, y, z #for loop
and use min and max to update the value of an indicator with each evaluation.

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