A little help along the way

Follow these steps. Every option is explained underneath. Everything happens in your browser; the model is never sent anywhere.

Open the modelDrop it on the page or press Choose a file. An OBJ shows its colours when its .mtl file and pictures are chosen with it; a .gltf needs its .bin and pictures too. Choose them all at once.
Turn it roundDrag to turn it, scroll or pinch to zoom, and drag with the right mouse button or two fingers to move it. Fit brings the whole model back into view; Front, Top, Side and Corner look at it from those sides.
Say its size, if it has noneSTL, OBJ and PLY files do not say what their numbers mean. The page reads STL files in millimetres, as 3D printers and CAD programs write them; if the size looks wrong, choose the unit the file was made in.
Choose how fine curves are, for CAD filesSTEP, IGES and BREP files keep exact curves, which are cut into flat triangles to be drawn. Fine suits most parts; Very fine follows curves more closely and makes a larger model, Draft a quicker, coarser one.
Measure itThe size of its box is shown at once, with its surface area, and its volume when it is a closed shape. Press Measure, then two points on the model, for the distance between them; a press near a corner snaps to it.
Look insideCut slices through it across its height, width or depth. Parts lists every piece by name: hide one, or press it to see which it is.
Save a picturePicture saves a PNG of the model as it is shown, at the size set under More options, on a clear background if you like.

Every option explained

What it opens: GLB and glTF 2.0 (with Draco, meshopt and KTX2 compression), STL (binary and text), OBJ with MTL, PLY (meshes and point clouds), 3MF, Collada (DAE), USD (USDZ, USDA, USDC), FBX, CAD files (STEP, IGES and BREP), buildings (IFC), Rhino (3DM), and 3DS, OFF, AMF, VRML, X3D, LightWave, VTK, DirectX and older game formats. CAD, building and Rhino files are read by OCCT, web-ifc and rhino3dm, each downloaded from KeepSimp the first time it is needed.
Rhino files: openNURBS, Rhino's own library, reads a 3DM's surfaces but cannot cut them into triangles, so a surface shows only through the display mesh Rhino saved with it. A file saved with "Save small" has none, and its surfaces are left out and counted; meshes, point clouds, blocks and SubD shapes always show.
Closed shapes: A model is a closed shape when every edge joins exactly two faces turned the same way. Only then does it have a volume, and only then is one given. Holes, edges shared by three faces or more and faces turned the wrong way are counted and named.
Looks: Shaded, edges, wireframe, X-ray, normals (which way each face points, by colour) and a UV checker (how pictures are laid on it). Flat faces show every triangle; the backs of faces can be drawn too.
Which way is up: CAD programs, 3D printers and 3MF stand models on Z; glTF and most animation programs on Y. A model is turned to stand upright, never mirrored; change it under More options if it lies on its side.
Keys: F: fit the model to the window; 1: look from the front; 2: look from above; 3: look from the right; 4: look from a front corner; 5: switch between perspective and flat (orthographic) view; W: show or hide the wireframe; M: measure between two points; S: cut through the model; Space: play or pause its animation; Escape: stop measuring or cutting.
Not opened: Files that only their own program can read: .blend, .skp, SolidWorks parts, .max, .c4d, Inventor and Revit files. Export STL, OBJ, GLB or STEP from the program that made them.

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A little help along the way

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3D viewer

Drop a 3D file here

A little help along the way

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