Hi Spulber,
I checked the code provided by you, and it is my understanding that by providing the proper (x, y, z) triplet for each of the points and using the plot3 function instead of plot, you can transform your 2D plot into a 3D plot.
The modified sample code where I used plot3 in place of plot is as follows:
clc
close all
x=2;
y=2;
r=0.5;
t=0:0.1:2*pi;
x=r*cos(t)+x;
y=r*sin(t)+y;
a=[1,x];
b=[1,y];
for k=1:length(t)
clf;
a=[1,x(k)];
b=[1,y(k)];
plot3(x(k),y(k),1,'go','LineWidth',2)
hold on
plot3(x(1:k),y(1:k), ones(k,1),'k','LineWidth',1.5)
axis([0 4 0 4])
hold on;
plot3(a,b,[4 1],'r')
xlabel("x");
ylabel("y");
zlabel("z");
drawnow
end
