.stl — Stereolithography File
3D Systems · 1987
STL (Stereolithography) is the most widely used file format for 3D printing.
Key Features
- Varies storage behavior for typical 3d workflows
- Common MIME type: application/sla
- Recognizable file signature: 73 6F 6C 69 64 (solid, ASCII) or 80 bytes header (binary)
- Associated with 3D Systems
Best For
- Design and modeling pipelines
- Exchanging geometry or scene data
- Technical visualization
Less Ideal For
- Simple document sharing
- Quick photo publishing
- Low-complexity note taking
Common Use Cases
- 3D modeling and CAD workflows
- Game or product asset exchange
- Rendering and simulation pipelines
How to Open It
- On Windows, open the file with 3D Builder or Blender.
- On macOS, open the file with Blender or MeshLab.
- If the file does not open, confirm that the extension really matches .stl and that the download or transfer completed without corruption.
What is a .stl file?
STL (Stereolithography) is the most widely used file format for 3D printing. It describes the surface geometry of a 3D object using triangular facets without any color, texture, or material information. STL files come in both ASCII and binary formats, with binary being preferred for its smaller file size. The format's simplicity makes it universally supported by 3D printers, slicers, and CAD software.
Programs That Open .stl Files
| Platform | Program | ||
|---|---|---|---|
| Windows | 3D Builder | Free | Official |
| Blender | Free | ||
| Cura | Free | ||
| macOS | Blender | Free | |
| MeshLab | Free |
Common Problems with .stl Files
Frequently Asked Questions
.stl files can be opened with several programs. 3D Builder is one of the most popular choices.
Generally yes, .stl files are safe to open with appropriate software.
Yes, there are many online and offline tools available to convert .stl files. Check the conversion section above for specific methods.
Technical Details
Stereolithography File files use the application/sla MIME type and were first introduced in 1987 by 3D Systems. The file can be identified by its signature: 73 6F 6C 69 64 (solid, ASCII) or 80 bytes header (binary).