3d_visualisation

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

Answer 1

[Mike Garrity]

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.

[Reyhaneh S. Ghazanfari]

Many thanks Mike!

Reyhaneh