From help-octave-request at bevo dot che dot wisc dot edu Tue Jan 28 09:15:56 2003
Subject: 3D plotting with gnuplot
From: "Pete Watkins" <pkwatkins at fastmail dot fm>
To: help-octave at bevo dot che dot wisc dot edu
Date: Tue, 28 Jan 2003 06:27:56 -0600

I'm having trouble with simple 3D plotting of points via gnuplot. For
instance, as an simple example if I define a matrix describing
the four corners of a unit cube

"cube = [0 0 0; 0 0 1; 0 1 0; 0 1 1; 1 0 0; 1 0 1; 1 1 0; 1 1 1]"

and try and plot it

"gsplot cube with dots"

gnuplot seems to use the i and j indicies of the matrix for the x and y
coordinates, and the data as the z coordinate, resulting in a mess. In
contrast, if I save the matrix in an ascii file, cube.txt, and plot that
file with 

"gsplot 'cube.txt' with dots"

The four corners of the cube are plotted fine. Obviously I can overcome
the problem by saving an ascii file each time before I plot. However I am
doing real-time visualisation during a simulation, and writing/reading
ascii files at each timestep may slow it down somewhat.

Cheers,

Pete



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