STL File Type

- The quick facts

What are STL files and how to open them

Are you having problems opening a STL file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your files.

What is a STL file?

The .stl (STereoLithography) file extension was developed by Albert-Battaglin Consulting Group for the Standard Tessellation Language, a common CAD stereolithography format for 3D modeling and prototyping. STL files are also used in generating complex models that are popular in 3D printers and generators.

STL file extension is commonly found or used in 3D systems. This file extension that represents the data for making simple CAD models that appear in 3D set up. It changes the surface of the object by integrating tessellation. Tessellation is a tiling of a plane by using one or more geometric shapes, making sure that these shapes don’t overlap and produce no gaps between them. It transforms curves and planes that compose the curve into simple lines.

The CAD models appear in black and white 3D image. STL files usually use triangles in tessellating the object. By tessellating the model, .stl files are able to detect tiny areas in a model that has an imperfect spot before it is used.

How to open STL files

Important: Different programs may use files with the STL file extension for different purposes, so unless you are sure which format your STL file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested 10 different STL openers which you will find listed below.

Last updated: November 17, 2021

Suggest another file format using extension STL

While we know of one file format using the .STL file extension, there may be more. It is widespread that different programs use files with the same file extension for very different types of data. Please let us know if you are aware of a different kind of .STL file.

Various apps that use files with this extension

These apps are known to open certain types of STL files. Remember, different programs may use STL files for different purposes, so you may need to try out a few of them to be able to open your specific file.

FireworksFireworksUser submitted
Cadence Design System StmedCadence Design System StmedUser submitted
PSpice Stimulus EditorPSpice Stimulus EditorUser submitted
MeshmixerMeshmixerUser submitted
CuraCuraUser submitted
Jubler Subtitle EditorJubler Subtitle EditorUser submitted
Stimulus EditorStimulus EditorUser submitted
netfabb Studio Basicnetfabb Studio BasicUser submitted
MEGACADMEGACADUser submitted
MagicsMagicsUser submitted
We have not verified any software that we know for certain will work with STL-files on Mac. If you know one, please use the 'Suggest a program' link below and tell us about it!
We have not verified any web services that we know for certain will work with STL-files. If you know one, please use the 'Suggest a program' link below and tell us about it!