Online STL viewer

What an STL file is

STL (.stl) describes a surface as a list of triangles. It is what slicers for 3D printing read, and what most CAD and scanning software export for printing. It comes as binary (compact, the usual one) or ASCII text; this viewer opens both. An STL has no units, no colours and no separate parts: one file is one mesh, usually in millimetres.

What the viewer shows

• The mesh in 3D: left drag to rotate, right drag to pan, wheel to zoom, the cube in the corner for standard views.
• Display styles: shaded with edges, shaded, wireframe, to see the triangle density.
• Section: cut through the model to check wall thickness and hollow parts.
• Size: the overall dimensions, to check scale before printing.

STL, STEP and assembly manuals

An STL cannot become an assembly manual: the parts are not separated and their names are gone. STEP keeps both, which is why the manual workbench needs STEP (or IGES, in beta). Most CAD programs export STEP next to STL; see how to export STEP from your CAD. For STEP and IGES files, use the online STEP viewer.

Private by design

The file is read by JavaScript in your browser tab and is not sent to us or anyone else. See how files stay in your browser.

Questions

Is this STL viewer free?

Yes. No account, no limit on the number of files.

Does it open binary and ASCII STL?

Yes, both.

Can I make an assembly manual from an STL?

No. An STL is one mesh without separate parts. Export STEP from your CAD instead and open that in the workbench.

Can it repair or convert an STL?

No. It only views the file.

More guides

• Online STEP viewer
• STEP file to assembly instructions
• An exploded view from a STEP file, without a CAD licence
• Your STEP file stays in your browser
• Guides
• Export a STEP file from SOLIDWORKS
• Export a STEP file from Fusion (Fusion 360)
• Export a STEP file from Onshape
• Export a STEP file from FreeCAD
• Export a STEP file from Autodesk Inventor