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How t generate cone using scattered random point cloud?

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M.S. Khan
M.S. Khan on 20 Oct 2020
Commented: M.S. Khan on 4 Mar 2021
Using the below code, i have geneated sphere. could anyone please guide me how to geneate cone using random scattered point cloud.
I will be very thankful. Thanks in advance to all community members for their cooperation and guidance. Regards
r = randn (10000,3);
r = round(bsxfun(@rdivide,r,sqrt(sum(r.^2,2)))*130);
x = r(:,1);
y = r(:,2);
z = r(:,3);
scatter3(x,y,z)
  3 Comments
M.S. Khan
M.S. Khan on 20 Oct 2020
They are using grid that means its uniform spaced points? Could you guide me how to generate cone using scattered random point cloud.

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Accepted Answer

Bruno Luong
Bruno Luong on 20 Oct 2020
Edited: Bruno Luong on 20 Oct 2020
This code provides the uniform distribution on the surface of the cone
h = 3; % height
r = 1; % base radius
n = 1e4; % number of points
topcapflag = true; % include the top cap or not
rho = sqrt(rand(1,n));
z = h*rho;
if topcapflag
z(rand(1,n)<r/(h+r))=h;
end
theta = (2*pi)*rand(1,n);
rho = r*rho;
x = cos(theta).*rho;
y = sin(theta).*rho;
% graphic check
figure
plot3(x,y,z,'.')
axis equal
  1 Comment
M.S. Khan
M.S. Khan on 21 Oct 2020
Thanks Dearest Bruno for your professional supprot. Regards!

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More Answers (1)

Ameer Hamza
Ameer Hamza on 20 Oct 2020
This is one way. The distribution is non-uniform
h = 2; % height of cone
r = 1; % maximum radius of cross section of the cone
n = 10000;
z = rand(1, n)*h;
t = rand(1, n)*2*pi;
r = interp1([0 h], [0 r], z);
[x, y] = pol2cart(t, r);
scatter3(x, y, z)
  15 Comments
M.S. Khan
M.S. Khan on 4 Mar 2021
Ameer Hamza, what about the cap of the cone? is it be closed or open?

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