3MF viewer online — open .3mf files with colours, no upload
View 3MF files from MakerWorld, Printables, Bambu Studio, Cura or PrusaSlicer right in your browser: every object in the file with its colour, size, volume and mass. Measure it, cut a cross-section, export a part as STL — nothing is uploaded.
Measure
Click a part to isolate it and see its own dimensions.
Dimensions & mass
Load a model to see its dimensions, volume, surface area and mass.
Cross-section
Measuring tips
- Snap is on by default — clicks land on the nearest corner or edge vertex, which is where CAD tessellations keep exact dimensions.
- Hole diameters: click three points spread around the rim (not in a line). The fit is a true 3D circle, so it works on tilted faces too.
- Units: STEP/IGES are read in millimetres from the file. Mesh formats carry no units, so the tool applies each format’s convention — if a model looks 10×, 25×, or 1000× off, switch File units rather than the display unit.
- Mass multiplies the closed-mesh volume by the material density — pick the right material, and expect open or hollow meshes to read low.
- X-ray + cross-section together show internal pockets, wall thickness and hidden holes.
Capabilities
What the 3mf viewer does
- Opens .3mf files instantly in the browser — multi-object models keep each object’s name and basematerial colour, so multi-part downloads look the way they were published.
- Dimensions, volume, surface area and mass by material for the whole model or any single object, in mm, cm or inches.
- Watertight check on every object: open edges and flipped faces are flagged before you waste a print, with a one-click link to the repair tool.
- Point-to-point distances, angles and hole diameters with snapping to corners and edges; cross-sections on any axis with the section area.
- Export any object as STL or GLB, save the parts list as a CSV, or take an annotated screenshot.
- 100% private: the file is read on your device, never uploaded. No account, no watermark, no install.
Process
How it works
- Drop the 3MFDrag a .3mf from your downloads onto the viewer. The archive is unpacked and rendered locally in a second or two.
- Browse the objectsOpen the parts list to isolate any object and read its own dimensions, volume and mass; switch to X-ray to see inside.
- Check, measure, exportVerify it’s watertight, measure critical features, then export a part as STL, download the parts CSV, or send it to the online slicer.
Downloads
How to open a 3MF file from MakerWorld or Printables
Most model sites now publish 3MF instead of STL because one file can hold several objects, their colours, names and even print settings. You don’t need a slicer to look inside: drop the file here and every object appears in the parts list with its colour and size. Isolate a part to check it, measure a hole or a clearance, and export just that part as STL if you only want to print one piece. When you are ready to print, the online slicer accepts the same 3MF and turns it into G-code without installing anything.
Formats
3MF vs STL — why slicers prefer 3MF
STL stores a single bare mesh with no units, colours or names. 3MF is a zipped XML package that stores many objects with metadata, materials, units and optional slicer settings, and it is smaller for the same geometry. That is why Bambu Studio, PrusaSlicer, Cura and OrcaSlicer save projects as 3MF. The catch: painted colour regions from Bambu/Orca (AMS painting) live in vendor-specific metadata that generic viewers cannot render — this viewer shows each object’s base colour, not paint strokes. Need a plain mesh for an older tool? Use the 3MF to STL converter.
Notes
Good to know
- Shows each object’s basematerial colour; Bambu Studio / OrcaSlicer paint (per-face AMS colouring) and slicer print profiles stored in the 3MF are not rendered.
- 3MF units are read from the file (almost always millimetres); switch File units if a model was saved in another unit.
- Very large multi-object files load on desktop browsers but can exceed a phone’s memory.
- Measurements are taken on the mesh; curved features are as accurate as the mesh resolution the author exported.
FAQ
Questions, answered
What is a 3MF file?
3MF (3D Manufacturing Format) is the modern 3D-printing file format: a zipped XML package that can hold several objects with names, colours, units and slicer settings. MakerWorld, Printables, Bambu Studio, PrusaSlicer and Cura all use it.
Can I open a 3MF file without Bambu Studio or Cura?
Yes — drop it here. The viewer unpacks and renders the file in your browser, shows every object with its colour and dimensions, and lets you measure or export parts without installing a slicer.
Does the viewer show the colours from the 3MF?
It shows each object’s base material colour as stored in the file. Per-face paint from Bambu Studio or OrcaSlicer (AMS painting) is stored in vendor metadata and is not rendered.
Is my 3MF file uploaded to a server?
No. The file is parsed and rendered on your own device with WebGL — it is never uploaded, there is no account and no watermark. Close the tab and nothing is left behind.
How do I convert a 3MF to STL?
Select an object in the parts list and download it as STL straight from the viewer, or use the 3MF to STL converter to export the whole file.
Can I check whether the 3MF will print?
The viewer flags open edges and flipped faces per object. For bed fit, filament weight and cost, run the printability checker, or load the same file in the online slicer.
What is the maximum file size?
Up to 300 MB. Very large meshes (millions of triangles) load on a desktop browser but can exceed the memory of a phone; the closed-mesh check is skipped above 1.5 million triangles to keep things responsive.
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