OneTaskBy Tim King · Updated
3MF Viewer
Open 3MF 3D Printing Files in the Browser, Free
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How the 3MF Viewer works
This 3MF viewer opens 3D printing files without installing a slicer. Drop a .3mf exported from PrusaSlicer, Bambu Studio, Cura, Fusion or a model site, and the page shows every part as it sits on the build plate, with its colours, so you can orbit, zoom, read the size and part count and save a PNG. The file stays in your browser and is never uploaded.
3MF viewer: why 3MF needs its own reader
3MF, the 3D Manufacturing Format, was published by the 3MF Consortium in 2015 to replace STL. It is a zip package of XML files that can hold several objects, their positions on the plate, colours and materials, the units they were drawn in and print settings. Many slicers now save projects as 3MF by default, which is why a downloaded model often arrives as a .3mf rather than an .stl. Ordinary 3D viewers and operating systems frequently cannot open it.
What the viewer shows
Each build item in the package is placed with its transform, scaled from the file's declared unit, millimetres by default, and coloured from its base materials. The rail shows the number of build items and mesh parts, the triangle count and the overall size. Wireframe and normals modes help spot thin walls and flipped faces. Slicer-specific settings inside the package, such as layer height or supports, are not read.
Checking a model before printing
Look at the part count before slicing: a plate with more items than expected may include supports or test pieces the designer left in. For dimensions in millimetres, volume and a watertight check on a single part, export it as STL and use the STL dimensions checker.
FAQ
Can it open a Bambu Studio or PrusaSlicer project?
Yes, the geometry and plate layout load. Project files also contain slicer settings, filament profiles and sometimes sliced G-code, which the viewer ignores. Multi-plate projects show every plate's objects together.
Why is my model lying on its side?
3MF is defined as Z up, which the default respects. A few exporters write Y up; switch the Up axis menu and the model will stand upright.
Can I convert the 3MF to STL here?
Not on this page, which is a viewer. Most slicers can export a loaded 3MF as STL. Use the PNG button to save an image of the model for notes or listings.
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