MATLAB: 3d_visualisation

3d visualisationMATLAB

Hello!
I have drawn a 3d surface using the surf function. I would like to visualize the 3D volume enclosed between this surf and the x-axis. Would that be possible in Matlab?
Thanks!
Reyhaneh

Best Answer

There are some utilities for this on the file exchange, and there is the isocaps function which works with isosurface, but there isn't a builtin utility for adding "skirts" to the surface that the surf function creates.
It's actually relatively easy to do by hand. Here's a simple example:
% Create some interesting sample data
[x,y,z] = peaks;
z = z+3;
x = x(20:end,20:end);
y = y(20:end,20:end);
z = z(20:end,20:end);
[m,n] = size(z);
% Create the original surface
surf(x,y,z);
% Create 4 surfaces around the edges
hold on
walls(1) = surf([x(  1,:); x(  1,:)],[y(  1,:); y(  1,:)],[zeros(1,n); z(  1,:)])
walls(2) = surf([x(end,:); x(end,:)],[y(end,:); y(end,:)],[zeros(1,n); z(end,:)])
walls(3) = surf([x(:,  1), x(:,  1)],[y(:,  1), y(:,  1)],[zeros(m,1), z(:,  1)])
walls(4) = surf([x(:,end), x(:,end)],[y(:,end), y(:,end)],[zeros(m,1), z(:,end)])
set(walls,'FaceColor','interp')
But this only works if all of your Z values are on one side of the origin. If they cross, you need to do something similar to what I described in this blog post about a similar 2D problem.
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