first u need to know:
- how the data is stored (in 2D it is very straightforward, but not in 3D): is it slice by slice (which plane, xy,xz,or yz)
- data type and format (binary, or integer?)
- data size for each dimension x,y,z
fileid = fopen('mydata.dat','r');
data = fread(fileid, inf, 'single', 'ieee-be'); %read till the end of file
data = reshape(data,[dimx dimy dimz]); % reshape data
