Free 3MF Viewer — Open & View 3MF Files

Open 3MF files online, free. See every part, read true millimetre dimensions, measure and X-ray the model, then edit it and export 3MF, STL or OBJ. No install.

Open any 3MF file in your browser.

Someone sent you a .3mf and nothing on your machine will open it. Drop it here and every part loads on the build plate at its real size, ready to inspect, measure, and (if you want) change.

Free · Runs in your browser · No account needed

See what is actually in the file

A 3MF carries more than a shape: several separately named parts, each with real-world units. Most quick previews flatten all of that into one silhouette.

Every part, listed

A 3MF usually holds several objects rather than one lump. Each arrives as its own entry in the scene tree, keeping the name, part type and display colour the file gave it — so you can select, hide, and inspect them one at a time instead of staring at a merged grey silhouette.

Real dimensions, not guesses

3MF records its own units, and OwlCAD works in true millimetres throughout, so the size you read is the size it prints. Measure edges, hole radii, arc lengths, face areas, and the gap between two parts, and check bounding size, volume, and triangle count.

Checked before you slice

Run the print check for thin walls, overhangs, and non-watertight geometry, and repair the mesh in place: the problems worth finding before a multi-hour print, not after it.

Then change it if you need to

A plain viewer stops at looking. Here the same window scales to exact dimensions, cuts and combines with other shapes, and exports back to 3MF, STL, OBJ, GLB, or STEP.

Open a 3MF now

View it, measure it and edit it, all in the browser, with no download.

What happens to your file

It opens on your device, it is saved to your workspace as you work, and it exports back out in the format your slicer wants.

No upload queue

Your browser reads and renders the model itself, so it appears as soon as you drop it in — you are never queued behind anyone else’s upload, and the file does not travel anywhere before you can see it.

Saved, not discarded

Most online viewers forget your file the moment you close the tab. OwlCAD keeps the model in your own workspace and syncs it as you work, so it is still there when you come back to this browser. Create a free account and it follows you to any device, and your projects dashboard lets you delete anything you no longer want.

Exports to a real file

When you are done, export STL, 3MF, OBJ, GLB or STEP — the format your slicer or your colleague actually needs, not a project file that only opens here.

Frequently asked questions

How do I open a 3MF file without installing anything?

Drop the .3mf into OwlCAD in your browser and it opens on the build plate straight away, with no install and no sign-up to look at it. You can orbit, zoom, and switch on X-ray to see inside the model.

Will it show all the parts in a multi-part 3MF?

Yes. A 3MF often holds several objects rather than one lump, and each arrives as its own item in the scene tree, so you can select, hide, and inspect them individually instead of seeing a single merged blob.

Is the size shown in the file correct?

Yes, and this is where 3MF beats STL. A 3MF records its real-world units, and OwlCAD works in true millimetres throughout, so the dimensions you read are the dimensions the part will print at, with no guessing whether a model arrived in inches.

Can I measure a 3MF, or check it before printing?

Yes. Measure edges, radii, arc lengths, face areas, and gaps, read the bounding size, volume, and triangle count, and run the print check for thin walls, overhangs, and non-watertight geometry before it reaches your slicer.

Can I change the model, or only look at it?

You can change it. Unlike a plain viewer, the same window is a full editor: scale to exact dimensions, cut and combine with other shapes, repair the mesh, and export back to 3MF, STL, OBJ, GLB, or STEP.

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