STL files (Stereolithography), also known as Standard Tessellation Language, are the file format used to save 3D models. STL files are the most common file type used in 3D printing, especially for home desktop 3D printers. Nearly all software packages that interface with 3D printers accept STL files. The STL file format works well for 3D printing because it describes the item’s surface geometry which translates well into a printable model.
There are a lot of powerful design tools, both for the home user and commercial programs, which export to STL. Some of these may require an extension or plugin to export as an STL. This is another reason STL files are a great pick when designing and printing 3D models.
When using an STL file in 3D printing, keep in mind that it only describes the surface of the 3D object. It doesn’t include the color, texture or other common CAD model attributes. In 3D printing, the STL file must be sent through the 3D printer’s interfacing software, which slices the model and determines how the object will be 3D printed, layer by layer. Without this slicing process, the 3D printer will not be able to read and print the STL file.
There may be a new file format on the horizon. Cimatron, a leader in CAD/CAM software solutions, announced a software release called AMF (Additive Manufacturing File) that is an XML-based format. Unlike STL files, AMF has support for color, materials, lattices, and constellations. The software is expected to be released mid-2014.