A file with .stl extension is a 3D graphic file native to Stereolithography technology. Stereolithography is basically a type of 3D printing technology to create 3D models. What is an STL file?

Not all of the models are in formats that we can read — maybe some of you can? — but there are STL files galore in the “3D Printing” folder. These include a printable Curiosity rover ...

A mark of a good 3D print ... This Slinky model was made using a few lines of JavaScript that output a Gcode file. There is no .STL file, and you can’t edit this CNC Slinky in any CAD ...