5 Facts About STL Files


Stereolithic (STL) files have become synonymous with 3D printing. Also known as “Standard Triangle Language,” this otherwise common file format is used in countless 3D printing applications. Both consumers and businesses alike use it to design objects for 3D printing. Even if you’re familiar with the term, though, there are probably some things about STL files that you don’t know. Here are five surprising facts about STL files.

#1) The Most Common File Format for 3D Printing

While 3D printers often support a variety of file formats, STL is the most common. More consumers and businesses use STL files for 3D printing than any other file format. Many 3D printers use STL as their default file format, whereas other 3D printers support the format.

#2) Invented in the 1980s

Many people assume that STL files are new, but this isn’t the case. They’ve actually been around since the late 1980s. The STL file format was pioneered by the Albert Consulting Group in 1987. At the time, the format was designed specifically for commercial-grade 3D printers. Since then, it’s made its way into consumer-grade 3D printers as well. Today, STL is the most common file format used in both commercial- and consumer-grade 3D printers.

#3) Little Has Changed Since Its Inception

Although it’s been over two decades since the STL file format was invented, little has changed regarding its specifications. The format still uses the same instructions to guide a 3D printer during its object-building operations as it did back in the late 1980s. With that said, an update for the STL file format was proposed in 2009, but even with this update, the format continues to mirror the original STL file format.

#4) Describes Surface Geometry

STL files are designed to describe the surface geometry of printed objects. They don’t contain instructions for color or texture — which is often used in other computer-aided design (CAD) files. Rather, STL files only contain instructions for surface geometry. The simple nature of STL files is one of the reasons why they’ve become so popular over the years.

#5) ASCII and Binary Versions

The standard STL format uses an ASCII format. Due to the large size of ASCII files, though, there’s a binary version available. The binary version of STL has a header that supports up to 80 characters. More importantly, it’s significantly smaller than its ASCII counterpart. The smaller size of binary STL files makes them preferable for complex 3D printing applications.

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