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

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

Answer 1

[Alan Stevens]

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

[Don jaya]

Is it possible to change the size of the spheres? like by changing the radius/diameter or the shperes.

[Alan Stevens]

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

This sets the size of all the points to be the same.

If you want some to be set at different values you would need to plot them with seperate plot commands.

[Don jaya]

Thanks alot