stlwrite

R2026b

Create STL file from triangulation

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Syntax

stlwrite(TR,filename)
stlwrite(TR,filename,fileformat)
stlwrite(___,Name=Value)

Description

stlwrite(TR,filename) writes a triangulation TR to a binary STL file filename. The triangulation can be either a triangulation object or a 2-D delaunayTriangulation object.

example

stlwrite(TR,filename,fileformat) also specifies a file format for the written file. fileformat can be either "binary" (default) or "text".

example

stlwrite(___,Name=Value) specifies additional options for writing to the STL file using one or more name-value arguments for either from the previous syntaxes. For example, stlwrite(TR,"stlbinary",Attribute=attributes) also writes a uint16 vector of attributes for each triangle in TR.

Examples

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Open Live Script

Create a triangulation representing two intersecting rings and write the result to an STL file.

To represent the first ring, define a torus surface with the internal radius of 1 and external radius of 5.

R = 5;
r = 1;
angle = linspace(0,2*pi,50);
angle(end) = []; % Omit the repeated point for 0 and 2pi
[theta,omega] = meshgrid(angle,angle);

Define the coordinates x, y, and z to represent a torus.

X = (R+r.*cos(theta)).*cos(omega);
Y = (R+r.*cos(theta)).*sin(omega);
Z = r.*sin(theta);

Create an alphaShape object with an alpha radius of 2. 

shp = alphaShape(X(:),Y(:),Z(:),2);

Extract triangulation from the boundary surface of alphaShape. This triangulation represents the first ring.

[tri,xyz] = shp.boundaryFacets;
t1 = triangulation(tri,xyz);

Define the second ring by rotating the triangulation.

t2 = triangulation(tri,xyz*[1 0 0;0 0 1;0 1 0] + [4 0 0]);

Combine the two triangulations.

Points = [t1.Points;t2.Points];
Connectivity = ...
[t1.ConnectivityList;
    t2.ConnectivityList + size(t1.Points,1)];
trCombined = triangulation(Connectivity,Points);

Plot the resulting triangulation.

p = trisurf(trCombined);
p.EdgeAlpha = 0.4;

Two intersecting torus-shaped ring surfaces plotted as a 3D triangulation mesh

Create an STL file from the triangulation.

stlwrite(trCombined,"Rings.stl");
Open Live Script

Create and plot a 2-D triangulation object. 

P = [2.5 8.0;
     6.5 8.0;
     2.5 5.0;
     6.5 5.0;
     1.0 6.5;
     8.0 6.5];
T = [5 3 1;
     3 2 1;
     3 4 2;
     4 6 2];
TR = triangulation(T,P);
triplot(TR)

2-D triangulation with four triangles connecting six vertices

Write the triangulation to a text file named tritext.stl.

stlwrite(TR,"tritext.stl","text")

Input Arguments

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Triangulation, specified as a triangulation object or a 2-D delaunayTriangulation object.

STL file name, specified as a character vector or scalar string. The file name must end with the .stl or .STL extension.

Example: "stltextfile.stl"

File format, specified as either "binary" or "text".

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: stlwrite(TR,"stltext",SolidIndex=solidIDs)

Binary attributes, specified as a uint16 vector. When the input file is a binary file, attributes can contain coded information about the triangles. Its length must be equal to the number of triangles in the triangulation. This parameter is not supported when the input file is a text file.

Solid grouping index, specified as a vector of identification numbers. When the input file is a text file, the identification numbers must assign each triangle to a grouping of triangles in the triangulation. The length of the vector must be equal to the number of triangles in the triangulation. This parameter is not supported when the input file is binary.

Extended Capabilities

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Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

Version History

Introduced in R2018b

See Also

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