Free Online STL Viewer
Open an STL, 3MF or OBJ file right in your browser. Turn the part around, read its size in millimetres and inches, and check its volume and whether the mesh is watertight — before it goes to a printer, a vendor or a colleague.
Drop an STL, 3MF or OBJ file here, or click to choose
Read in your browser — nothing is uploaded
Private by design
Your file is opened by your browser and never uploaded. That matters for unreleased products and customer parts under NDA: nothing about the file leaves your computer unless you send it.
Measured, not just drawn
Overall size in millimetres and inches, volume, surface area, triangle count, and a watertight check that tells a pinhole from a real tear. Parts that look like they were exported in inches get a one-click ×25.4 fix.
Will it print in one piece?
The viewer checks the part against our standard printers (256 mm) and our large-format machines (up to 600 mm), in any orientation.
Supported formats
- STL — binary and ASCII, from any CAD package or scanner.
- 3MF — including Bambu Studio project files. Parts are drawn and measured where the plate places them, at the scale set in the slicer; a multi-part plate is measured as a whole.
- OBJ — triangles and polygons; materials and textures are ignored.
- STEP / STP — not supported in the browser (CAD solids, not meshes). Export an STL or 3MF, or send the STEP with an order.
Questions
Is my file uploaded?+
No. The file is read and measured by your own browser, on your own computer. Nothing is sent to us or anyone else unless you choose “Price this part” or “Order it printed”.
Is it free? Do I need an account?+
It's free, with no account, no sign-up and no limit on how many files you open.
Which file types does it open?+
STL (binary and ASCII), 3MF — including Bambu Studio project files — and OBJ, up to 150 MB. STEP files are CAD models rather than meshes, so no browser viewer can measure them; export an STL or 3MF from your CAD tool.
Why does my part look tiny?+
STL files don't store units. A part drawn in inches and exported without converting reads as millimetres, so a 2-inch part shows as 2 mm. If the size looks like that, the viewer offers to treat it as inches (×25.4) and can save a corrected STL.
What does “watertight” mean, and why does it matter?+
A watertight mesh is a closed surface: every edge is shared by two faces, with no holes. Volume — and so weight and price — can only be calculated honestly on a closed surface. Small gaps are common and a slicer closes them; a torn mesh needs repairing before it can be quoted from geometry.
Can I convert a 3MF to STL?+
Yes. Open the 3MF and choose “Download as STL”. The STL holds the same triangles; colours and print settings stored in the 3MF aren't carried over, because STL has nowhere to put them.