Alan,
Thanks for the reply. MATLAB and SCILAB functions are overloaded to
allow to this. For example the following figures were generated by such
a call to surf(x,y,z), with x, y, and z each a n-by-n matrix.
I believe this causes the function to trace curves of constant u and v,
though I am not sure. I use it to make 3-dim cardioid patterns.
I believe the following wound work (with some mods).
u = linspace(min,max,n);
[U,V] = meshgrid(u,u);
define some functions.
X(U,V), Y(U,V), Z(U,V)
then
surf(X,Y,Z).
if u and v are theta and phi in spherical coordinates, then
sin(Th).*cos(Ph), sin(Th).*sin(Ph), cos(Th) would generate the unit sphere.
Thanks,
David
On 3/20/2018 10:09 PM, Alan W. Irwin wrote:
On 2018-03-20 17:05-0400 David Bergman wrote:
All,
I am interested in making a surface plot in 3-dim of a parameterized
surface in the following format,
x(u,v), y(u,v), z(u,v)
rather than the usual z = f(u,v).
MATLAB, SCILAB, and Octave have this option and I was wondering if
PLplot has it as well.
I did look through the examples and documented interfaces and nothing
seemed to match this.
Hi David:
Our plcont and plshades API's have this capability, see
<http://plplot.org/docbook-manual/plplot-html-5.13.0/plcont.html> and
<http://plplot.org/docbook-manual/plplot-html-5.13.0/plshades.html>,
but our other means of making 3D plots, e.g., plmesh (see
<http://plplot.org/docbook-manual/plplot-html-5.13.0/tri-d-plots.html>
for the full list of our 3D API's) have only one-dimensional x and y
arguments.
By the way, can you give me an example of, say, a mesh plot of a
parameterized surface? I thought such plots required one-dimensional
x and y vectors since the results are typically a collection of 3D
lines, z(y)_i, at a fixed set of one-dimensional x_i values and
another set of 3D lines, z(x)_j, at a fixed one-dimension set of y_j
values. In fact, all the MATLAB examples I have just looked up of
mesh plots seem to be of this type.
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and
Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________
Linux-powered Science
__________________________
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