3MF Viewer

A 3MF viewer for 3D printing files

This 3MF viewer opens .3mf files in your browser so you can see what is in a print file without launching a slicer. Drop the file on the page and every object in it appears, with its 3MF colors, in the positions they were arranged in. The file stays on your computer; nothing is uploaded.

It is handy for a quick look at a model downloaded from a printing community, for checking a project file someone shared, or for opening a 3MF on a computer that has no slicer installed.

What 3MF is and why slicers switched to it

3MF (3D Manufacturing Format) is maintained by the 3MF Consortium, an industry group founded in 2015 by Microsoft together with companies from the 3D printing and CAD world. It was designed to replace STL, which cannot say how big a model is, what color it is or how several parts fit together.

A 3MF file is a ZIP archive. Inside is an XML file (usually 3D/3dmodel.model) with the meshes, plus optional thumbnails, textures and metadata. Because the XML is compressed, a 3MF is typically much smaller than the same model as STL.

PrusaSlicer, Bambu Studio, OrcaSlicer, UltiMaker Cura and other current slicers can save their whole project as 3MF, including printer and filament settings in their own extra files inside the archive.

Units

Stored. The file declares millimeters, inches, meters or another unit, so there is no guessing about scale.

Multiple objects

Stored and shown. Each object and each placed copy (a "build item") keeps its position.

Colors and base materials

Stored and shown when defined with the standard 3MF materials and colors.

Slicer settings

Stored by the slicer in its own files. Ignored by this viewer, which shows the geometry only.

Beam lattices and slice stacks

Specialized 3MF extensions for industrial printing. Not supported here.

Colors you painted in a slicer may not appear

Multi-color painting in PrusaSlicer, Bambu Studio and OrcaSlicer is usually saved with slicer-specific attributes rather than the standard 3MF color definitions. Other programs, including this viewer, may not understand those attributes, so a model you painted in four colors can show up in one.

Colors defined with standard 3MF materials, as written by many CAD programs and some exporters, do display.

Viewing tips

3MF files are opened Z-up, the way printers and slicers see them, so the model sits on the build plate. If an object still appears on its side, use the up-axis toggle.

The info panel shows the number of objects (meshes), the triangle count and the overall size in the file's units. A slicer project with several plates shows all objects together, at the positions they were given.

For the older single-mesh printing format, see the STL Viewer.

Converting a 3MF file

Use "Download as" to save the model as STL, OBJ, GLB, glTF, PLY or USDZ. STL is the usual choice when a printer, print service or older program does not accept 3MF. Be aware that STL keeps only geometry: colors are lost, all objects are merged into one mesh, and the unit information is dropped, so the numbers stay as they were in the 3MF.

To create an STL for a program that does not read 3MF, use 3MF to STL.