View
Preview an STL instantly on the STL viewer page, or upload it to measure, section and share it.
The STL File Format
STL describes the surface of a 3D object as a list of triangles. It is the standard input format for 3D printing slicers.
.stlStereolithography (STL)
What is an STL file?
An STL file stores only geometry: each triangle has three corner points and a normal. There are no colours, materials, textures or units, and no record of how the shape was designed.
STL comes in two encodings. ASCII STL is readable text and large; binary STL is compact and far more common. VIZON opens both.
When to use STL
Good for
- Sending a model to a 3D printing slicer
- Sharing a simple shape between tools
- Scans and downloaded printable models
Not ideal for
- Precise engineering changes (use STEP and CAD)
- Coloured or textured models (use GLB)
How to open, edit and create STL files online
Edit
Open it in the 3D Model Creator to scale, rotate, cut, combine, split or decimate it.
Create
Design a part in VIZON CAD and export STL in millimetres, ready for your slicer.
STL compared with other 3D formats
| Format | Geometry | Units | Materials | Animation | Best for |
|---|---|---|---|---|---|
| STEP / STP | Exact solids (B-rep) | Stored | Colours only | No | CAD exchange, manufacturing |
| STL | Triangles | Not stored | No | No | 3D printing |
| GLB | Triangles + scene | Metres | PBR + textures inside | Yes | Web, AR, games |
| glTF | Triangles + scene | Metres | PBR, textures beside | Yes | Web pipelines |
| FBX | Triangles + scene | Stored | Yes | Yes | Game engines, DCC tools |
Related guides: How to Edit an STL File Without Blender, STL vs STEP
STL file questions
How do I open an STL file online?
Drop it on the VIZON STL viewer page for an instant preview, or upload it to your VIZON library to open it in the full viewer.
Can I edit an STL file?
Yes, as a mesh. VIZON can resize, rotate, cut, combine parts, split and decimate STL files. For precise dimensional changes, rebuild the part in CAD.
What units does an STL use?
None are stored. Slicers usually assume millimetres.
Open your STL file in VIZON
Upload it to your library and open it in the browser, on any computer.