This file will import and plot ASCII STL file in MATLAB.

readSTL( filename)

function [ coordinates] = readSTL( filename)
% reads ASCII STL file and gives coordinates of vertices.
%filename-name of file(test.stl)
fid=fopen(filename);
C=textscan(fid,'%s');
%reads file and generates cell.
k = cellfun(@length,C);
%gives number length of the array.
m = 11;
i = 1;
while(m < (k-3))
j = 1;
while (j < 4)
l = 1;
while(l<4)
coordinates(i,1) = str2double(C{1,1}{m,1}); % took 3 days, 10 odd questions on mathworks.com to write this line :).
% data in cells were in 'char' format .convert it to double as
% matrix cant store 'char's.
l = l+1; % makes sure loop runs thrice.
m = m+1; % access corresponding row from cell'C'.
i = i+1; % row number in output matrix.
end
m = m+1;
j = j+1;
end
m = m+9;
end
% plotting file using patch command.
S = size(coordinates,1);
T = S(1,1);
n = 1;
while(n<T)
o = 1;
while(o<4)
D = rand(3,1);
X(o,1)= coordinates(n,1);
n = n+1;
Y(o,1)= coordinates(n,1);
n = n+1;
Z(o,1)= coordinates(n,1);
n = n+1;
o = o+1;
end
patch(X,Y,Z,D);
hold on;
end
end