This might be a good starting point:
[x,y,z] = ndgrid(1:5:100,1:5:100,1:5:100);
scatter3(x(:),y(:),z(:),'.')
The ndgrid function will return multiple arrays of the same shape with one of its inputs replicated along one dimension of each of its outputs.
The syntax x(:) says to convert that 3D array into a vector.
The scatter3 function takes 3 vectors and plots a marker at the location defined by each row of the three.
The '.' argument to scatter3 tells it to draw a dot, rather than one of the bigger and more complex markers.
