You can download a 3D volume from the following link:
http://vda.cs.univie.ac.at/Teaching/Vis/Data/Volumes/

Submit your report with tomato.vol volume but feel free to experiment with the other volumes as well.

Volumes are unsigned 8-bit integers. The first 11/12 characters are the size of the volume in ASCII, separated with space character (32), and ends with NL character (10). You can simply cut the first 12 characters from uncbrain.vol and 11 characters from the rest.

To make it easier, I have provided the sequence of commands you need to laod the file:

%Open the data file and load data
fid = fopen( 'example.vol', 'r' );
[data1D, count] = fread(fid, 'uint8');

%Find the boundaries of data pieces
delim = find(data1D == 32, 2);
data_offset = find( data1D == 10, 1 );

%Calculate the size of each dimension
size_x = 0;
for i=1:( delim(1)-1 )
size_x = 10 * size_x + (data1D(i)-'0' );
end

size_y = 0;
for i=( delim(1) + 1 ):( delim(2)-1 )
size_y = 10 * size_y + (data1D(i)-'0' );
end

size_z = 0;
for i=( delim(2) + 1 ):( data_offset-1 )
size_z = 10 * size_z + (data1D(i)-'0' );
end
%OR just set them manually from the info files in the website.

%Reshape the data from 1D to 3D
data3D = reshape( data1D(data_offset+1:count), size_x, size_y, size_z );

fclose(fid);