STL (Stereolithography / Standard Tessellation Language)
STL is the most widely used 3D file format for 3D printing and rapid prototyping. It describes the surface geometry of a 3D object using triangular facets (meshes) without color, texture, or material information.
MIME Type
model/stl
Type
Binary
Compression
Lossless
Advantages
- + Universal standard for 3D printing and slicing software
- + Extremely simple format — easy to generate and parse
- + Supported by every 3D printer and slicer
Disadvantages
- − No color, texture, or material information
- − No support for curves — all geometry is triangulated
- − No units — scale must be agreed upon externally
When to Use .STL
Use STL for 3D printing and prototyping; use glTF or OBJ for applications needing color, texture, or animation.
Technical Details
STL files contain a list of triangular facets, each defined by a normal vector and three vertices. The format comes in ASCII (human-readable) and binary (compact) variants. Binary STL is 80 bytes header + 50 bytes per triangle.
History
Chuck Hull (inventor of stereolithography) created STL in 1987 for 3D Systems' early 3D printers. Despite its limitations, STL became the de facto standard for 3D printing due to its simplicity.