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From: "Jan Simon" <matlab.THIS_YEAR@nMINUSsimon.de>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Calculate whether a point is above or below a plane
Date: Mon, 12 Jul 2010 18:59:06 +0000 (UTC)
Organization: Universit&#228;t Heidelberg
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Dear Ian,

If you have 50k points, you can rotate the 3D coordinates such that the normal vektor of the plane is parallel e.g. to the Z-axis.
Then a simple >= operation of the Z-component of the points is enough to decide if they are over or under the plane.

Jan