How to create randomly placed points within a 3D rectangle?

Question

Don jaya 2020-8-28

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https://ww2.mathworks.cn/matlabcentral/answers/585872-how-to-create-randomly-placed-points-within-a-3d-rectangle

评论： Don jaya 2020-8-28

I want to create random points (solid spheres which i can change the radius) inside a 3D rectangular box, which i can change the dimensions of the box later. I found this code for a randomly place points inside a function and i could like to know if anyone knows how to change it to a rectangle.

% pick plenty of random points
x = -1 + (1+1)*rand(1,500); %x-coordinate of a point
y = -0.6 + (0.6+0.6)*rand(1,500); %y-coordinate of a point
z = -0.8 + (1.2+0.8)*rand(1,500); %z-coordinate of a point
%function defining a heart
F1=(((x.^2) + (9/4).*(y.^2) + z.^2-1).^3+(-x.^2 .* z.^3 -(9/80).*y.^2.*z.^3));
ind = F1<0;                   % index for points inside the isosurface
x = x(ind);  x = x(1:100);    % pick 100 of those points
y = y(ind);  y = y(1:100);
z = z(ind);  z = z(1:100);
scatter3(x, y, z, 'MarkerFaceColor','b','MarkerEdgeColor','b');
hold off

https://www.mathworks.com/matlabcentral/answers/352222-how-to-create-randomly-placed-points-within-a-3d-figure

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Answer 1

Alan Stevens 2020-8-28

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https://ww2.mathworks.cn/matlabcentral/answers/585872-how-to-create-randomly-placed-points-within-a-3d-rectangle#answer_486530

在 MATLAB Online 中打开

Do you mean something like this:

% length, width and height of box
L = 3; W = 2; H = 1;
% pick plenty of random points
x = L*rand(1,100); %x-coordinate of a point
y = W*rand(1,100); %y-coordinate of a point
z = H*rand(1,100); %z-coordinate of a point
scatter3(x, y, z, 'MarkerFaceColor','b','MarkerEdgeColor','b');
box

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Alan Stevens 2020-8-28

在 MATLAB Online 中打开

Yes, try:

% length, width and height of box
L = 3; W = 2; H = 1;
% pick plenty of random points
x = L*rand(1,100); %x-coordinate of a point
y = W*rand(1,100); %y-coordinate of a point
z = H*rand(1,100); %z-coordinate of a point
blob = 10;
plot3(x, y, z,'o', 'MarkerFaceColor','b','MarkerEdgeColor','b','MarkerSize',blob);
box