STL is an interchange file format supported by numerous CAD applications and used for storing 3D models of various parts and prototypes. STL files are used for 3D printing through Stereolithography, a method also known as "solid free form fabrication" or "photo solidification".

Rigid objects created through Stereolithography are built by successively adding thin layers of curable material, one on top of the other. One of the main advantages of using this 3D printing technique is speed. STL files are facet based representations of solid entities. During the output process, CAD system attributes such as color or layer are ignored.

How to open STL Files

There are two types of STL storage files that can be opened with various applications, depending on their nature. ASCII based ones are human readable and can be viewed and edited with any text editor. However, because they can reach large sizes, they're generally used only for debugging.