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How can I animate the drawing of a figure 8 shape in a polar plot to confirm the path it takes?

Asked by Omar Ahmed on 20 Jun 2018
Latest activity Commented on by Omar Ahmed on 20 Jun 2018
Here is my code, where I am taking a figure 8 shape on a polar plot and rotating it around. I want to confirm the path that each figure 8 is drawn by animating it.
start = 0;
end_ = 2*pi;
disc = pi/16;
theta4 = 0:0.01:2*pi;
rho4 = sqrt(4*cos(2*theta4).*(sec(theta4).^4)); % figure 8 function
for i=0:31;
interval = start+i*disc:0.01:end_+i*disc;
%subplot(4,4,i+1)
polarplot(interval,rho4)
hold on
pause(0.2)
end

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1 Answer

Answer by Steven Yeh on 20 Jun 2018
 Accepted Answer

Try this:
start = 0;
end_ = 2*pi;
disc = pi/16;
theta4 = 0:0.01:2*pi;
rho4 = sqrt(4*cos(2*theta4).*(sec(theta4).^4)); % figure 8 function
figure()
stepSize = 20;
for i=0:31
interval = start+i*disc:0.01:end_+i*disc;
for k = 1:stepSize:length(rho4)
endPoint = min(k+stepSize, length(rho4)); % avoid array boundary exception
polarplot(interval(k:endPoint), rho4(k:endPoint));
hold on
pause(0.2)
end
end
The stepSize variable used to set the speed of the animation
You can set the color in the outer i loop