3MF Viewer
Open a .3mf to see every object with its colours, check sizes and print estimates, or extract the geometry as STL.
- Multiple objects
- Colours
- Print estimates
- No upload
Drop a 3MF file here.
Drag to rotate · scroll or pinch to zoom · right-drag or two fingers to pan
What is a 3MF file?
3MF (3D Manufacturing Format) is the modern replacement for STL, developed by the 3MF Consortium. It is a ZIP package of XML that can hold several objects, colours, materials and real units, and slicers such as PrusaSlicer, Bambu Studio and Cura save whole print projects as 3MF. This viewer reads the model geometry and colours, reports size, volume and estimated weight, and exports the geometry to STL. Slicer settings inside the project are ignored.
How to open a 3MF file
- Choose Open File and pick your 3MF (add its textures or material files too), or drag them onto the viewer.
- Drag to rotate, scroll or pinch to zoom, and right-drag or two-finger drag to pan.
- Switch between shaded, wireframe and X-ray, use the view buttons, or cut a section to see inside.
- Read the size, volume and triangle count, measure between two points, then export or take a snapshot.
Tips for checking a print
- STL has no units. Most printing files are in millimetres; if a model looks 25 times too small, it was probably exported in inches.
- A watertight mesh is required for an accurate volume. If the check fails, repair the model in your slicer or in Meshmixer.
- Use the section view to check wall thickness and hidden internal geometry.
- Weight estimates assume 100% infill; with typical 15–20% infill and walls, expect 30–50% of the solid weight.
Why use this 3MF viewer
- Measure, not just lookDimensions, triangle count, surface area, volume and a watertight check, plus click-to-measure distances and a section view.
- Print estimatesSolid weight and 1.75 mm filament length for common materials, from the exact mesh volume.
- Watertight checkFind holes and non-manifold edges that cause slicing errors, before you waste a print.
- Your model stays on your deviceFiles are read and rendered in your browser with WebGL. Nothing is uploaded, so unreleased products, client work and scans stay private.
Supported 3D formats
| Format | Files | Typical use |
|---|---|---|
| STL | .stl | Triangles only (ASCII or binary); the standard for 3D printing |
| 3MF | .3mf | Modern print format with objects, colours and units |
| OBJ | .obj + .mtl | Text format from modelling tools; materials and textures in separate files |
| glTF / GLB | .gltf, .glb | Web and AR standard with PBR materials and animations |
| FBX | .fbx | Autodesk exchange format for animation and game engines |
| PLY | .ply | Scans and point clouds, often with vertex colours |
| Collada, 3DS, AMF, VRML | .dae, .3ds, .amf, .wrl | Older exchange and print formats |
Common uses
- Before slicing. Check orientation, scale and holes.
- Downloads from Thingiverse or Printables. Preview files without installing software.
- Quoting prints. Get volume and weight for pricing.
- CAD exports. Confirm an export from Fusion, SolidWorks or Onshape came out right.
More file tools: view SVG images as PNG, inspect photo metadata or convert images to ICO icons.
Example: checking a downloaded print project
Open a 3MF from Printables. It contains 4 objects, 32 cm³ in total, about 40 g of PLA before infill savings.
What to expect from the result
Colour STL variants are shown when present. Volume and weight assume a closed mesh. Extremely large files are limited by your browser’s memory.
3MF Viewer questions
How do I open a 3MF file without a slicer?
Choose Open File and select the .3mf. The objects appear in your browser with their colours.
Can I convert 3MF to STL?
Yes. Choose Export → STL to save all objects as one binary STL.
Are slicer settings shown?
No. Print settings stored by slicers are ignored; only the models are displayed.
How is the volume calculated?
The viewer adds up the signed volumes of tetrahedra formed by each triangle, the standard method for closed meshes. It is only meaningful when the model is watertight, which the viewer checks for you.
Are my 3D files uploaded?
No. The viewer runs entirely in your browser using WebGL; the file is never sent to a server and the page keeps working offline once loaded.