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version (1.51 KB) by Bill McDonald
Write STL file from surface data.


Updated 24 Feb 2004

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Editor's Note: This file was selected as MATLAB Central Pick of the Week

SURF2STL Write STL file from surface data.
SURF2STL('filename',X,Y,Z) writes a stereolithography (STL) file
for a surface with geometry defined by three matrix arguments, X, Y
and Z. X, Y and Z must be two-dimensional arrays with the same size.

SURF2STL('filename',x,y,Z), uses two vector arguments replacing
the first two matrix arguments, which must have length(x) = n and
length(y) = m where [m,n] = size(Z). Note that x corresponds to
the columns of Z and y corresponds to the rows.

SURF2STL('filename',dx,dy,Z) uses scalar values of dx and dy to
specify the x and y spacing between grid points.

SURF2STL(...,'mode') may be used to specify the output format.

'binary' - writes in STL binary format (default)
'ascii' - writes in STL ASCII format



See also SURF.

Author: Bill McDonald, 02-20-04

Cite As

Bill McDonald (2020). surf2stl (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (40)


Hello. I have a point cloud [X, Y, Z] matrix with x,y and z coordinates. How can I use this code to write a STL file with the surface?


fid == -1 and is always unable to write stl?

Devon Jakob

I have 6 variables: for Large sphere X,Y,Z and small sphere mounted over it P,Q,R and i want to convert the surf plot of these two sphere into a .stl file. Can you please help me?


It works super good. But is it possible to change the direction of the normal vectors from pointing to the inside to pointing to the outside?


Joe Hansen

V slick my dude.


great work Thanks

Adam Yock

This was exactly what I needed. Thanks! Worked without any issues.

John Pope

filename='link0_test.stl'; %base
cyl_height = 0.1;
precision = 40; % increase to obtain a more accurate drawing

%create a unit height cylinder with 100 points. Radius 75
[X,Y,Z] = cylinder([cyl_radius], precision);
%Multiply Z by height

%Save in stl format, create new file
surf2stl(filename, X, Y, Z, 'ascii', 'w');

%now create a disk, bottom
radius = linspace(0,cyl_radius,precision); % For ten rings
theta = (pi/180)*[0:15:360]; % For eight angles
[R,T] = meshgrid(radius,theta); % Make radius/theta grid
X = R.*cos(T); % Convert grid to cartesian coordintes
Y = R.*sin(T);

%append this solid to already created file, bottom disk
surf2stl(filename, X, Y, 0.*X, 'ascii', 'a+');
%top disk
surf2stl(filename, X, Y, cyl_height.*ones(size(X,1), size(X,2)), 'ascii', 'a+');

John Pope

forget previous comment. digging through google results.... supposedly you need a meshgrid

[X,Y] = meshgrid(-2:.2:2, -4:.4:4);
Z = X .* exp(-X.^2 - Y.^2);

John Pope

This really could be simplified by moving the dimension detections within function (size(L):rows,size(L):cols)

here's how I got it working....

L needs to be 2 dimensional (rows,cols) l!!!!!

L = -0.1136 -0.1932 -0.0031 0.0593 -0.2272
0.2525 0.5000 0.9647 1.0000 0.0593
0 0 0 0.9647 -0.0031
0 0 0 0.5000 -0.1932
0 0 0 0.2525 -0.1136


I'm trying to convert my .m file to a .stl file and I am having a hard time using this function. What do I put into the x y z componets in the surf2stl?

Tyler Moore

Is there a way to create a volume using this script? I have the .stl surface, but want to extend that to some "ground" so I can print it with a 3D printer.

Hi. I have cute solids by using trisurf(tri,xmesh,ymesh,zmesh,colorVector), where x(nx1), y(nx1), z(nx1) and tri(n/2 x 3). But, unfortunately it does not run at your surf2stl. Do you have any idea how can I run trisurf2stl? Thank you.

Does not work anymore


Hi, I am trying to get MATLAB to output STL files of chaotic systems (Rossler, Lorenz, Chua). The graphs are made from iterating x, y, and z in a for loop. So I converted the vectors into a matrix using the vec2mat command. It gave me the STL files but the lines have no thickness. How can I resolve this problem? I tried adding space below the graph but it just makes a cylinder shape and doesn't thicken the lines. Please advise.


L = 40*membrane(1,25);
[rows cols] = size(L);
x = 1:rows;
y = 1:cols;

And voila! You can 3D print the Matlab logo! (or any other surface for that matter) =)

LEGAL NOTE: This may violate copyrights or trademarks. I am not liable if you choose to do this.

Thanks for the awesome code!

Please help I get a flat gray surface, is it because my x ,y, are vectors and not meshgrid?


Really usefull for my research with flow over different surfaces

Man great submision. I have used it to make some geek gif in my blog.


Thanks for this file! You save me a lot of time! Very helpfull

Jay Berger

nice work bill. i'm wondering about how one would go about adding labels to such stl files. such as, adding little spheres in a surface plot at a certain location (say x = 10, y = 10) and add labels such as "x = 10 & y = 10" at that location.

@ Prashanth,
AFAIK, .stl is inherently meant for triangulated geometry representation.

What you can do is to split rectangles into triangles - e.g. rectangle (n1, n2,n3,n4) gives two triangles - (n1,n2,n3) and (n3,n4,n1). Note that the order of n1,n2 etc is such that the normals obtained by cross product of vector, say n1_n2 x n2_n3 points outwards direction and there is consistency in this normal direction among all triagles. i.e. no sudden flips.

hope it helps,

Hi Bill,

What changes to be made in the program to get a stl with rectangular grid instead of triangular grid



But you could speed it up - it counts at large meshes, if you could find a way to avoid the for loop. For calculating the surface normals, you could use "surfnorm".

Great job! Thanx a lot!

Daniel Lopes

Thanks Bill! You made a very useful MATLAB function for geometric modeling purposes.
Woks just fine!

Bin Huang

Awesome! It helps me alot.

Max Lingamfelter

Very nice program. Does anyone know a way to write the STL file while keeping other data intact to describe the color?

Yoel Shapiro

Very helpfull! I tried for a long time to open a MATLAB generated mesh or vrml in different 3D environments and couldn't. This did the job.

Amanda L

very neat. Used for converting small pieces of scarcely digitized bone surface point clouds to STL surface which can be loaded into Mimics and Amira.

Mike M

Has good nift. Use with gridgen to make mathematical surfaces into stl files for cfd. mmmm

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