What is the difference between TIN vs STL?

In this short article you will learn about the differences between TIN vs STL files.

What is a TIN File?

Triangular irregular networks (TIN) are a popular form of digital geographic data that have been used for many years by the GIS and CAD communities.  TINs are formed by triangulating a set of vertices that are connected with a series of edges to form a network of triangles. When trying to calculate volume, planimetric area and surface area for engineering purposes TINs are the high-precision modeling file of choice.

What is an STL file?

Stereolithography (STL) is a file format used for 3D printing.  The STL format was created by 3D Systems in 1987 in support of their commercial 3D printing technology.  Similar to a TIN, the file contains data that describes the surface geometry of a 3D object, created by linked triangles.

The STL format provides two different ways to store geometric information – ASCII encoding and binary encoding. For each format, the information stored includes 1) the coordinates of the vertices and 2) components of the normal vector of each triangle.


On the surface (pun intended), TIN and STL files may appear to be similar – both represent the surface of a 3D model with triangles.  The difference is that each file format was designed to work with different software, and this is where the nuance lies.  A TIN file created in AutoCAD Civil 3D, for example, may be designed specifically for the Civil 3D workflow.  Meanwhile, the STL file format offers specific advantages for 3D printing.  For example, triangle sorting – in an STL file, triangles may appear in ascending z-value order to help slicing software slice the model faster.

Convert TIN to STL

If you are googling “convert TIN to STL” you are probably a civil engineer or landscape architect who has amazing topography or a design in CAD software that you want to 3D print or CNC.

If you have your own design already (e.g. Civil 3D proposed surface), and you want to convert from TIN to STL, check out this article.

If you don’t have a design, and you are looking to 3D print or CNC existing topography, check out Equator’s 3D print functionality, or try out the link below.

Frequently Asked Questions

TIN stands for Triangular Irregular Networks.

STL stands for Stereolithography but has been given other acronyms after the fact such as “Standard Triangle Language” and “Standard Tessellation Language”.