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┌─ FILE ANALYSIS ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
DEVELOPER : 3D Systems
CATEGORY : 3D
MIME TYPE : model/stl
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What is an STL file?

STL (Stereolithography or Standard Tessellation Language) is a file format that describes the surface geometry of 3D objects using triangular facets. Created by 3D Systems for stereolithography CAD software, STL has become the universal format for 3D printing. It stores only geometry — no color, texture, or material information.

How to open STL files

  • Cura (Windows, macOS, Linux) — Free 3D printing slicer
  • PrusaSlicer (Windows, macOS, Linux) — Free slicer
  • Blender (Windows, macOS, Linux) — Free 3D editor
  • MeshLab (Windows, macOS, Linux) — Free mesh viewer

Technical specifications

PropertyValue
GeometryTriangle mesh (facets)
FormatsASCII or Binary
Normal VectorsPer-facet (outward-facing)
ColorNot supported (standard)
UnitsNot specified (convention-dependent)

Common use cases

  • 3D printing: The primary format for FDM/SLA printers.
  • Rapid prototyping: Physical prototype production.
  • CAD export: Simplified geometry from CAD models.
  • Medical: 3D-printed anatomical models and implants.