MATLAB: How to get random points from upper semisphere

Question

Hello eveyone,

I use this code to get random points from a sphere with radius 5:

clear all

clc

fullFileName = fullfile(pwd, 'DataPoints.txt')

% Open a text file.

fileHandle = fopen(fullFileName, 'wt');

% Write out the things we want to write out.

rng(0,'twister')

rvals = pi*rand(100,1)+pi/2;

azimuth = 2*pi*rand(100,1);

[x,y,z] = sph2cart(azimuth,rvals,5);

figure

plot3(x,y,z,'.')

axis equal

fprintf(fileHandle, '{%f, %f ,%f},',[x,y,z]');

fprintf(fileHandle, '[%f, %f ,%f],',[x,y,z]');

fprintf(fileHandle, '%f, %f , %f;',[x,y,z]');

% Close the file.

fclose(fileHandle);

% Open it in notepad (Windows OS only)

winopen(fullFileName);

, but I want to have random points from upper semisphere with this radius.

Thanks in advance.

Answer 1

Put

...
[x,y,z] = sph2cart(azimuth,rvals,5);
z = abs(z)
...