Since the dawn of 3D printing, a little over three decades ago, there has been one file format that has dominated communicating with 3D printers — STL. Love it or hate it, and even with its limitations and shortcomings, STL has remained the de facto standard for the 3D printing industry. That may finally be changing, though, with the advent of more contemporary and robust file formats for 3D printing, such as AMF and 3MF. Over the next couple weeks we’ll be discussing the evolution, advantages, and disadvantages of 3D printing file formats, starting this week with STL.
So What Exactly Is An STL File?
Essentially, an STL file stores information about 3D models, but this format describes only the surface geometry of a 3D object without any representation of color, texture, or other common model attributes.
As it has been for three plus decades, the STL file format is still by far the most commonly used file format for communicating with 3D printers.
The true meaning of the file extension .STL has always been somewhat of a mystery. I’ve always considered it be an abbreviation of the word STereoLithography, although sometimes I have also heard it referred to as Standard Triangle Language or Standard Tessellation Language. Which is correct? Probably all of them.
Introduction To The STL File Format
The main purpose of the STL file format is to encode the surface geometry of a 3D object using tessellation. Tessellation is the process of tiling a surface with one or more geometric shapes with no overlaps or gaps. Having no gaps is especially important, as an object must be watertight to be printed. A good real life example of tessellation is a tiled floor.