Need to plot x^2+y^2=z^2; plot in 3D ; also obtain 2D cut in xy plane. How od I do this. Thanks

Need to plot x^2+y^2=z^2; plot in 3D ; also obtain 2D cut in xy plane. How od I do this. Thanks

Answer 1

[Björn]

There are several ways to do this. First you need to create the x- and y- arrays. This can be done using:

 x=x_min:dx:x_max
 y=(y_min:dy:y_max)'

x_min, y_min are the minimum values you want for x and y respectively. x_max, y_max are the maximum values. And dx, dy are the step-size between the different points. I take the transpose of y to be able to use BSXFUN so you don't have to create a loop to create the z-matrix.

The z-matrix can then be created by:

 z=bsxfun(@plus,x.^2,y.^2)

note that the z-value is in fact z^2.

Next you can plot the 3D-surface using:

 surf(x,y,z,'linestyle','none')

The part: 'linestyle','none' suppresses the gridlines, which in the case of a big matrix, you don't want to be shown.

Now if you want to have a 2D cut (or intensity-graph) in the xy plane, you add the command:

 view(0,90) % Shows graph from top-view
 camva(7)  % Camera viewing angle. Alter to increase or decrease size of plot

Hope this is what you are looking for.