STLA_TO_TRI_SURFACE
Convert data from ASCII STL to TRI_SURFACE format

STLA_TO_TRI_SURFACE is a MATLAB program which reads data from an ASCII STLA file describing a triangular mesh of a 3D surface, and converts it to a pair of arrays describing a triangular mesh or TRI_SURFACE.

Especially if you are reading large ASCII STL files, you might want to consider the "fast" version of the program, which uses the routines STLA_SIZE_FAST and STLA_READ_FAST, provided by Bill Seufzer of NASA Langley.

An ASCII STL file contains a description of the surface of a solid that has been decomposed into triangles. The vertices of the triangles should be listed in counterclockwise order, as viewed from outside the surface. A normal vector for the triangle may also be listed.

A TRI_SURFACE or triangulated mesh surface, is described by a pair of arrays:

• a node coordinate array containing the coordinates of nodes;
• a triangle node array containing triples of the indices of the nodes used to form each triangle;

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

OBJ_TO_TRI_SURFACE, a MATLAB program which reads an OBJ file and extracts the surface mesh data as a TRI_SURFACE dataset.

PLY_TO_TRI_SURFACE, a MATLAB program which reads a PLY file and extracts the surface mesh data as a TRI_SURFACE dataset.

STLA, a data directory which contains a description and examples of STLA files.

STLA_DISPLAY, a MATLAB program which reads an ASCII STL file and displays it.

STLA_IO, a MATLAB library which reads or writes a PLY file.

STLA_TO_TRI_SURFACE_FAST, a MATLAB program which is a faster version of stla_to_tri_surface.

TRI_SURFACE, a data directory which contains examples of TRI_SURFACE files.

TRI_SURFACE_DISPLAY, a MATLAB program which displays a TRI_SURFACE dataset.

TRI_SURFACE_IO, a MATLAB library which reads and writes the 3D graphics information in a TRI_SURFACE file;

TRI_SURFACE_TO_PLY, a MATLAB program which converts TRI_SURFACE data to data suitable for storage as a PLY file.

TRI_SURFACE_TO_STLA, a MATLAB program which reads a TRI_SURFACE dataset and extracts the surface mesh data as an ASCII STL file.

Reference:

1. 3D Systems, Inc,
   Stereolithography Interface Specification,
   October 1989.

Source Code:

• stla_to_tri_surface.m the source code.

Examples and Tests:

CUBE is a cube using 12 triangular faces and 36 nodes.

• cube.stl the ASCII STL file.
• cube_nodes.txt the TRI_SURFACE nodes file.
• cube_elements.txt the TRI_SURFACE element file.
• cube.png, a PNG image of the shape;

MAGNOLIA is a magnolia blossom, using 1247 triangular faces and 3741 nodes.

• magnolia.stl, the ASCII STL file;
• magnolia_nodes.txt the TRI_SURFACE nodes file.
• magnolia_elements.txt the TRI_SURFACE element file.
• magnolia.png, a PNG image of the shape;

You can go up one level to the MATLAB source codes.