How to get heat colors with plot3d in scilab?

Question

Hi this may seem to be a simple question but I am having a hard time understanding how to use the colors in a plot3d.

That is what I have:

// x, y and z are matrix 4 by 100

myColors = ones(1,size(z,2));
plot3d(x,y,list(z,myColors),alpha=0,theta=270);

I would like to have myColors related to the altitude of z.

Answer 1

Code

If I understand correct x, y and z are something like:

x = [ 1:100 ];
y = [ 1:4 ];

z = rand( length(x), length(y) ); //Some function resulting in (100 x 4) matrix

Then you can plot it using the following code.

plot3d( x, y, z, alpha=0, theta=270);

e = gce();        // Get current entity handle.
e.color_flag = 1; // Color according to z

f = gcf();                        // Get current figure handle.
f.color_map = hotcolormap(512);     // Make it a heat color map

Docs

According to the plot3d docs and surface_properties docs the color_flag can be used to:

color_flag: This field is used to specify the algorithm used to set facets' colors.

Note that the rules on color_mode, foreground and hiddencolor are still applied to this case.

...

color_flag == 1

All facets are painted using one color index per facet proportional to z. The minimum z value is painted using the index 1 color while the maximum z value is painted using highest color index. The edges of the facets can be additionaly drawn depending on the value of color_mode (see above).

Resulting image