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Free 3MF Viewer Online — Preview Your Print Projects

If you've saved a project in Bambu Studio or PrusaSlicer, you already have 3MF files — they're the native save format for both slicers.

Last updated Mar 2026

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When to Use 3MF Viewer

Bambu Studio Project Preview

Bambu Studio saves projects as .3mf files containing your model, plate layout, AMS color assignments, and all print parameters. Preview the geometry before opening in Bambu Studio — useful when downloading shared projects from MakerWorld or receiving files from collaborators. Check that all parts are present and color zones are assigned correctly.

Multi-Color Print Verification

Printing with Bambu Lab AMS or Prusa MMU? Preview your 3MF to verify that color zones are assigned to the correct filament slots. A mis-assigned color zone means wasted filament and a ruined multi-hour print. Checking in the viewer takes 10 seconds.

Shared Project Inspection

Received a 3MF from a colleague or downloaded from a community? Preview the contents before opening in your slicer. Check whether it's a single model or multi-part assembly, verify the geometry quality, and confirm that the model is actually printable before committing your printer time.

STL vs 3MF Migration Check

Converting your workflow from STL to 3MF? Preview both versions to confirm that the 3MF correctly captured colors, materials, and multi-object layout that STL couldn't store. This is especially important for multi-part assemblies where STL requires separate files per part but 3MF bundles everything together.

Mobile Quick Check

Browsing MakerWorld or Printables on your phone? Preview downloaded 3MF files directly in the mobile browser without transferring to your desktop first. Check model quality and color assignments before deciding to print.

What You Should Know

Inside a 3MF File

A .3mf file is a ZIP archive (you can rename it to .zip and extract it). Inside you'll find: 3D/3dmodel.model (XML with geometry and materials), [Content_Types].xml (file type declarations), and optional directories for textures and thumbnails. The geometry section stores triangles with vertex indices, material IDs, and optional vertex colors. Print settings (layer height, infill, supports) are stored in separate XML metadata.

Why 3MF Replaced STL

STL is a list of disconnected triangles with no metadata. A 10cm cube and a 10-inch cube look identical in STL — only your slicer's unit setting determines the real size. 3MF defines units explicitly (millimeters by default), embeds colors and materials, supports multiple objects in one file, and stores print settings. File size is also smaller: 3MF uses indexed vertices and ZIP compression, making it 2-5x smaller than equivalent binary STL.

Slicer Compatibility

All major 2024+ slicers use 3MF natively: Bambu Studio (native project format), PrusaSlicer (native project format), Cura (import/export), OrcaSlicer (native), and Simplify3D 5.0+. Microsoft 3D Builder and Paint 3D also read/write 3MF. The only reason to use STL is compatibility with legacy slicers that haven't been updated since 2020.

Frequently Asked Questions
3MF (3D Manufacturing Format) is a modern 3D printing format that supports colors, materials, and metadata — features STL completely lacks. STL stores only triangulated geometry with no color, no material, no units, and no print settings. 3MF is backed by the 3MF Consortium (Microsoft, HP, Autodesk, Ultimaker, Stratasys) and is the recommended format for modern 3D printing.
All major modern slicers support 3MF natively: PrusaSlicer, Bambu Studio, Cura, Microsoft 3D Builder, Simplify3D, IdeaMaker, and Chitubox. Bambu Studio and PrusaSlicer use 3MF as their native project format — saving a project creates a .3mf file with the full print setup including supports, layer settings, and multi-material assignments.
Yes. The viewer displays geometry and color/material data from 3MF files. Multi-color models (for Bambu Lab AMS or Prusa MMU) will show the color zones. Full material support depends on the complexity of the 3MF package — basic vertex colors and material assignments are displayed.
Yes, in almost every way. 3MF is more compact (binary mesh data vs ASCII triangles), supports colors and materials, includes print settings (layer height, infill, supports), uses defined units (no ambiguity between mm and inches), and supports multiple objects in one file. The only reason to use STL is compatibility with very old slicers.
Yes. Bambu Studio saves project files as .3mf (which is a ZIP archive containing model geometry, print settings, and multi-color assignments). When you export from Bambu Studio for sharing, you get a .3mf file that preserves all your print settings. This viewer lets you inspect the geometry before opening in Bambu Studio.
Yes, use our 3MF to STL converter. Note that converting 3MF to STL loses all color, material, and print setting data — STL only stores geometry. Only convert to STL if your target slicer requires it. For modern slicers (Bambu Studio, PrusaSlicer, Cura), keep the 3MF format.

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Step-by-Step Guides

How to View and Inspect 3D Models Online Without Installing Software