John,
About this example:
> plot3d([u,v,2],[u,-3,3],[v,-3,3]);
I suspect the problem is that the function to be plotted is constant,
and that leads to a division by 0 in the plotting program.
Does plotting nonconstant functions work OK?
e.g. plot3d([u, v, u + v], [u, -3, 3], [v, -3, 3]);
or plot3d([u, v, u^2 - v^2], [u, -3, 3], [v, -3, 3]);
What is the operating system? Windows, Linux, something else?
What is the plotting program? It is specified by an option of
the form [plot_format, FOO] . If you didn't specify any such
option, then you'll get the default, which is Gnuplot.
Maxima writes a file which contains the points to be plotted
and tells the plotting program to read it. The file is named
maxout.FOO and it is written in the directory named by
the global variable maxima_tempdir . If you can locate that
file after a failed plot, please post its contents.
Thanks for helping us track down this problem.
Robert Dodier