POV-Ray : Newsgroups : povray.general : Bounding boxes... Server Time
26 Dec 2024 15:16:47 EST (-0500)
  Bounding boxes... (Message 1 to 1 of 1)  
From: Tim Nikias v2 0
Subject: Bounding boxes...
Date: 18 Mar 2003 18:41:52
Message: <3e77aec0@news.povray.org>
...aren't rotated or skewed, are they?

The problem is this:
if I'd want to project an object onto a planar surface,
I'd like to limit calculations for this.

My input is this:
Object and a rectangle, constructed with several
evenly spaced samples for mesh-calculation.

My idea:
Project a "shadow" of the bounding box onto the
planar-mesh and get the minimum and maximum
values of the indices covered. This rectangular section
will then use trace() to see if the nodes are actually
hit by the object.

To do all that properly, I'd like to know if using min_extent
and max_extent will get me the edges of the bounding box
with sides aligned to the axis'.

A different idea was to just take the center of the object,
project that onto the mesh to find the central node, then
calculate the maximum possible distance (by imposing the
shadow of a sphere, centered on the object, with the min_extent
and max_extent on or inside the sphere), and then simply take
the rectangular array of nodes which cover the entire shadow
of the sphere for more precise checking.

Hm. That seems to be the easier version. If anyone else
has ideas or comments on that, I'd like to hear 'em!

--
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.