.STL File Extension

A .STL file is a Certificate Trust List, created by 3D Systems.

Open with Autodesk Fusion 360. Available for Linux, Windows, and Mac.

What is a .STL file?

The file extension .STL stands for a type of file used in 3D modeling and printing. It is known as a Certificate Trust List. An STL file is a way to save a 3D model in what is called the Stereolithography file format. This format was developed by a company called 3D Systems. The content of an STL file can be in plain text or binary form. Both types of files describe the shape of a 3D model using a series of triangles. Each triangle is part of the surface of the model.

STL files are very popular and can be opened using a variety of computer programs that handle CAD (Computer-Aided Design) and 3D modeling. Some of these programs include Autodesk Fusion 360, Parametric Technology Creo, Dassault Systemes CATIA, and MeshLab. There are also specific viewers like Microsoft 3D Viewer and Microsoft 3D Builder that can open these files. Additionally, STL files can be viewed on different platforms such as Windows, macOS, and through online tools.

The history of STL files dates back to the late 1980s when Chuck Hull, co-founder of 3D Systems, patented the technology of stereolithography. This technology is primarily used for creating prototypes of products through 3D printing. The STL file format was one of the first to be used for storing 3D models for printing, which is why it is widely supported by many software programs today.

When you look at an STL file in a text editor, if it is a plain text file, you will see a list of the triangles that make up the model. Each triangle is described by its vertices and their coordinates. The file usually starts with the line "solid ModelName," indicating the beginning of the model data.

It's important to note that STL files can also be referred to by other names such as Standard Triangle Language files or Standard Tessellation Language files. These files are essential in the field of 3D printing and modeling, providing a way to share and print 3D designs.


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