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stlwrite - Write binary or ascii STL file

version (4.06 KB) by Grant Lohsen
This is an update to the excellent work done by Sven Holcombe to add color support


Updated 18 May 2012

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STLWRITE(FILE,fv) writes a stereolithography (STL) file to FILE for a triangulated
patch defined by FV (a structure with fields 'vertices' and 'faces').

STLWRITE(FILE,FACES,VERTICES) takes faces and vertices separately, rather than in an FV struct

STLWRITE(FILE,X,Y,Z) creates an STL file from surface data in X, Y, and Z. STLWRITE triangulates
this gridded data into a triangulated surface using triangulations options specified below. X, Y
and Z can be two-dimensional arrays with the same size. If X and Y are vectors with length equal
to SIZE(Z,2) and SIZE(Z,1), respectively, they are passed through MESHGRID to create gridded
data. If X or Y are scalar values, they are used to specify the X and Y spacing between grid

STLWRITE(...,'PropertyName',VALUE,'PropertyName',VALUE,...) writes an STL file using the
following property values:

MODE - File is written using 'binary' (default) or 'ascii'.

TITLE - Header text (max 80 characters) written to the STL file.

TRIANGULATION - When used with gridded data, TRIANGULATION is either:
'delaunay' - (default) Delaunay triangulation of X, Y
'f' - Forward slash division of grid quadrilaterals
'b' - Back slash division of quadrilaterals
'x' - Cross division of quadrilaterals
Note that 'f', 'b', or 't' triangulations require FEX entry 28327, "mesh2tri".

FACECOLOR - [nx3]- [red_1, green_1, blue_1; red_2, green_2, blue_2; ...; red_n, green_n, blue_n]
- N is the number of faces.
- range for colors is 5 bits (0:31).
- Only works in binary files.

Example 1:
% Write binary STL from face/vertex data
tmpvol = zeros(20,20,20); % Empty voxel volume
tmpvol(8:12,8:12,5:15) = 1; % Turn some voxels on
fv = isosurface(tmpvol, 0.99); % Create the patch object
stlwrite('test.stl',fv) % Save to binary .stl

Example 2:
% Write ascii STL from gridded data
[X,Y] = deal(1:40); % Create grid reference
Z = peaks(40); % Create grid height

Original idea adapted from surf2stl by Bill McDonald. Huge speed
improvements implemented by Oliver Woodford. Non-Delaunay triangulation
of quadrilateral surface input requires mesh2tri by Kevin Moerman.

Note: This entry was originally titled "patch2stl", however has been renamed to "stlwrite" after more general input was added.

Cite As

Grant Lohsen (2020). stlwrite - Write binary or ascii STL file (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (7)

Alexander Heinz

sandeep kundala

what should be the value of varargin?

Zhuowei Miao

Paul Kassebaum

Thomas Clark

Immediate bug using the STLWRITE(FILE,FACES,VERTICES) syntax:

'Attempted to access facecolor(:,1); index out of bounds because size(facecolor)=[0,0]'

Unfortunately, the options parsing code is pretty dense (much denser than it need be, I think) so rather than debug it myself, I'm shifting back to Sven's code.

Grant, you may find this submission useful; its a very convenient and robust way of options parsing:


Hi Chris, just a note that the stlwrite on which this file is based has facecolor implemented properly.

Chris Rorden

This is a useful tool. Unfortunately, Grant's new version has a small bug, which you can elicit by running "Example 1" from the help. To fix this bug, change the line
if isfield(options, 'facecolor')
to read
if isfield(options, 'facecolor') && (length(options.facecolor) > 0)

MATLAB Release Compatibility
Created with R2011a
Compatible with any release
Platform Compatibility
Windows macOS Linux

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