View an STL file in your browser
STL is the universal 3D-printing format — the mesh of triangles every slicer and CAD tool reads. Sometimes you just need to look at one: check it's the right model, see how big it is, count the triangles, or confirm a download isn't broken before you fire up a slicer. This viewer opens it in one drag, with no install and no account.
Everything happens in your browser. The file is read and rendered on your machine, and nothing is sent anywhere — handy for client work, paid models, or anything you'd rather not hand to a random web service. Drag to rotate, scroll to zoom, right-click-drag to pan, and hit Reset to re-frame if the model drifts off-screen.
STL, OBJ and 3MF — all in one viewer
As well as STL (binary or ASCII), this tool opens OBJ and 3MF files. For each one it shows the geometry plus an info row: triangle count, vertex count, and the bounding-box dimensions — enough to sanity-check a model's size and complexity before printing. A 3MF with several plates or parts is merged into one mesh for the preview.
Measure it and check it's printable
This isn't only a viewer — it's a quick pre-slice check. Switch the readout between millimeters and inches (and watch for the warning if a model is suspiciously small, the classic sign it was modeled in inches and will import 25.4× too small). Turn on Measure and click two points to read the distance and the X/Y/Z gap — handy for checking a hole, a peg or whether a part will fit. The panel also reports solid volume and surface area, the number of separate shells, and whether the mesh is watertight — flagging open edges (holes) and non-manifold edges that can trip up a slicer. The scale grid on the floor gives you a real-world size reference at a glance.
What the viewer shows — and what it doesn't
A plain mesh renders in a neutral gray, like an unpainted print, so you can read the shape clearly. A 3MF that carries color — Materials Extension color groups, Bambu Studio / OrcaSlicer painted faces, or per-part filament assignments — renders with those colors, and the Color button toggles them off when you want the bare geometry. What it doesn't do is edit: no painting, no mesh changes. If color is the point — multi-filament or AMS printing — don't stop at viewing: open the model in Layerpaint, paint per-region colors, and export a Standard 3MF your slicer prints in real filament. Need a different format? Use the 3MF ⇄ STL converter.