3D visualization with camtarget and campos

Dear,

I cannot solve this simple issue: I would like to perform a 3D plot tracking a point (let's say a cross) behind the track.

I tried campos and camtarget using a pre-existing example as follows:

clear all; clc; close all;
tf = 1;
dt = .01;

% Create a figure and a surface plot
fig = figure('position',[00 00 1000 700]);hold on;
centerfig
ax = axes;
[X,Y,Z] = peaks(50);
Z = Z/max(max(Z))*.5;

surf(ax,X,Y,Z);hold on;

% plot the trajectory
k=1;
for t = 0:dt:tf
    xt(k) = 2.0 * sin(2.0*3.14*0.2*t);
    yt(k) = 2.0 * cos(2.0*3.14*0.2*t);
    zt(k) = interp2(X,Y,Z,xt(k),yt(k),'cubic')+.2;
    k=k+1;
end

plot3(xt,yt,zt,'+','color','m');

% Set the camera viewing projection and angle
camproj('perspective');
camva(10);

t=20*dt;

% Camera position along the track
xp = 2.0 * sin(2.0*3.14*0.2*t);
yp = 2.0 * cos(2.0*3.14*0.2*t);
zp = interp2(X,Y,Z,xp,yp,'cubic')+.2;

% Camera target : 5 steps ahead
xnext = 2.0 * sin(2.0*3.14*0.2*(t+5*dt));
ynext = 2.0 * cos(2.0*3.14*0.2*(t+5*dt));
znext = interp2(X,Y,Z,xnext,ynext,'cubic')+.2;

axis equal
axis off
grid off
box off

campos([xp,yp,zp]);
camtarget([xnext;ynext;znext]);

drawnow

What I get is this:

The view does target the desired location but the point of view does not correspond to a point belonging to the track (5 steps before). What is wrong is my use of campos and camtarget?

Thanks, Petrus

[nitin harish]

Did you ever get solution to your problem, do you mind posting it here ?

[Petrus]

Unfortunately, no. Had to export data from matlab and to use dedicated 3D visualization (STK or similar). I am still interested in doing it in Matlab with those simple functions.

[Javier Ros]

Is seems that you need a loop, at least it is mising in your code.