3MF Viewer: open 3MF files without a slicer
A 3MF is a small ZIP package with one or more model files inside. The viewer unpacks it in the browser, applies the unit and the placement of every object, and shows what a slicer would put on the plate: objects, build items, size and colours, plus a check for open edges.
The 3MF is unpacked on this device
Drop a 3MF file here
Print files and slicer projects, also several at once
Unzipping and reading happen in this browser, the print file stays on your machine.
Model library
What is a 3MF file?
3MF stands for 3D Manufacturing Format. The 3MF Consortium, founded by Microsoft and a group of printer and software makers, published it as a modern replacement for STL. A file is a ZIP archive with XML inside: meshes as vertex and triangle lists, a unit for all numbers, and a build section that says which objects go on the plate and where.
Unlike STL, a 3MF can carry colours, materials, textures, several objects and their positions, and slicers add their own project data such as supports or print profiles. Because the unit is part of the file, a model drawn in inches does not shrink when someone opens it in millimetres, as long as the program reads the unit correctly.
What the 3MF tab shows
- Unit from the file
- Millimetre, centimetre, metre, inch, micron or foot as written in the 3MF, applied to every measurement.
- Objects and build items
- How many objects the package defines, how many of them are placed on the plate and how many model parts the ZIP contains.
- Real size and volume
- Width, depth and height in mm, cm or inches, volume and surface area of everything on the plate.
- Mesh check
- Open edges, edges with more than two faces and separate shells, the same test the STL export uses.
- Next step to STL
- One click hands the file to the 3MF to STL converter with the print preset.
Programs that open 3MF
- Slicers
- Bambu Studio, OrcaSlicer, PrusaSlicer and UltiMaker Cura save their plate setup as 3MF and read it back.
- Blender
- Reads and writes 3MF through an add-on, since there is no built-in importer.
- CAD programs
- Fusion, SolidWorks and other CAD tools export 3MF for printing.
Common 3MF problems and fixes
- The model is 25.4 times too small or too large
- The program that opened the file ignored the unit. A 3MF in inches shrinks by that factor when it is read as millimetres. This viewer applies the unit, so its size is a good reference.
- Some parts are missing
- Objects that are not listed in the build, for example spare parts kept for later, are not placed on the plate. Slicer projects sometimes spread objects over several model parts of the ZIP, and the viewer reads all of them.
- Colours look different than in the slicer
- Filament colours assigned in a slicer are often stored in its own project data, not as 3MF materials. The viewer shows the colours that the 3MF core format defines.
- Another program needs STL
- Use 3MF to STL. Geometry and size survive, colours and print settings stay in the 3MF.
Frequently asked questions
Can I open a 3MF file without a slicer?
Drop it on this page. The 3MF tab lists unit, objects and build items, and the view shows the plate in 3D. Nothing is installed and nothing is uploaded.
Is the size shown in millimetres?
The size uses the unit stored in the file and can be shown in millimetres, centimetres or inches. An inch file and a millimetre file of the same part show the same real size.
What is a build item?
An entry in the build section that places an object on the plate, with an optional transform for position and rotation. The same object can be placed several times.
Can I convert 3MF to STL here?
Yes. The 3MF to STL converter writes one binary STL in millimetres and checks it for holes. Colours, textures and slicer settings are not part of STL.
Are colours and textures shown?
Colours and base materials of the 3MF core format are shown, textures as far as the three.js loader supports them. Paint data that only a slicer understands is not read.
Convert 3MF files
Printable ideas from the Grab3D library
The library has no 3MF downloads. Convert a model with GLB to STL and import the STL into your slicer to save it as 3MF.