How to update a 3D surface plot?

I have a 3D cascade plot. It has Amplitude Vs Frequency data on X and Y axis. It has amplitude on Z axis. I want to create an animation where the evolution of data on X Y axis is updated slowly in the Z direction as the time progresses.

[Walter Roberson]

Which plot call did you use to create the 3D cascade plot?

[Anuj Rekhy]

I used the surf(X,Y,Z) to get the plot. Now I want to animate it with time.

Answer 1

[Star Strider]

See if modifying this code snippet with your surf call and data does what you want:

[X,Y] = meshgrid(linspace(-5, 5, 50));              % Create Mesh Data
fcn = @(x,y,k) k*x.^2 + y.^2;                       % Function To Plot (Vary Sign Of ‘x’)

v = [1:-0.05:-1;  -1:0.05:1];                       % Multiplier For ‘x’
for k1 = 1:2                                        % One Cycle For ‘Up’, One FOr ‘Down’
    for k2 = v(k1,:)                                % Select A Direction From ‘v’
        surfc(X, Y, fcn(X,Y,k2))                    % Draw Surface
        axis([-5  5    -5  5    -30  50])           % Set ‘axis’ For All Plots
        drawnow                                     % Draw Plot
        pause(0.1)                                  % Create Evenly-Timed Steps For Animation
    end
end

You will have to experiment with it to get the result you want.

Answer 2

[KSSV]

h.fig  = figure ;
h.ax   = handle(axes) ;                 %// create an empty axes that fills the figure
h.surf = handle( surf( NaN(2) ) ) ;     %// create an empty "surface" object

%Display the initial surface
set( h.surf , 'XData',X , 'YData',Y , 'ZData',Z )

for i = 1:n
    % update surface, load the data
    h.surf.ZData = Z ;
end

[Anuj Rekhy]

When I use the below command I directly get the whole graph and I cannot see any updation of the graph.

set( h.surf , 'XData',X , 'YData',Y , 'ZData',Z )

FYI, My X,Y,Z are all 2000x50 double matrix. That I am currently using to generate the 3D plot with the command surf(X,Y,Z).

[KSSV]

I guess X, Y remain same for the whole animation...you need to update only Z...so the above lines only updates Z.

[Anuj Rekhy]

Only X is constant in all the plots there are 50 plots for example. Then both the Y and Z values are changing in every frame and needs an update.

I am attaching a reference figure for your understanding of the problem. Here Time is Y data and the amplitude is Z data and X data is Frequency that is constant throughout.

I wanted to show time evolution of such a graph - such that it starts from zero and goes till 25 sec.

[Walter Roberson]

for i = 1:n
    Z = ... new data
    set(h, 'ZData', Z);
    drawnow()
end