Convert GLB to STL
Free GLB to STL converter that runs in your browser. See real dimensions before you download, and get a watertight, slicer-ready file.
Why convert GLB to STL?
GLB is the format you get from web viewers, AR tools, Sketchfab-style downloads and many AI 3D generators, but slicers want STL or 3MF. Two things make this conversion more than a rename. First, glTF and GLB work in metres and use a Y-up axis, while printing software expects millimetres and Z-up. MeshShift scales the model by 1000 to millimetres by default and can rotate it upright, so a 0.05 m figure becomes a 50 mm part instead of a 0.05 mm speck. Second, GLB often contains several meshes, materials and textures. STL keeps only the triangles, so the scene is flattened into one mesh and all colour and texture information is dropped.
How to convert GLB to STL
- Drop your GLB file (with its textures, if separate) onto the converter — it opens in your browser, nothing is uploaded.
- Check the preview and the dimensions in mm; fix units or the up axis in “Units & orientation” if the size or orientation looks wrong.
- Choose STL as the output (binary is smaller; ASCII is human-readable) and click Convert. Several files download as one ZIP.
What carries over from GLB to STL
| GLB | STL | Result | |
|---|---|---|---|
| Colour / materials | Yes | No | Dropped |
| Textures | Yes | No | Dropped |
| Units stored in file | Yes | No | Numbers in mm |
| Separate parts | Yes | No | Merged into one mesh |
| Usual up axis | Y | Z | Rotated (switchable) |
What changes
- Textures, vertex colours and PBR materials are discarded; STL stores geometry only.
- The scene hierarchy is flattened and all meshes are merged into one, with node transforms applied.
- Metres are scaled to millimetres (x1000) automatically; this can be switched off.
- The Y-up orientation can be corrected so the model stands upright in the slicer.
Tips
- Look at the dimensions shown before converting and type in a target height if the model has no real-world scale.
- Models made for games or AR are often open shells; run the free print check and repair before slicing.
- Thin details or single-sided surfaces may need thickening in a mesh editor, as GLB does not guarantee a solid.
- Several loose parts end up in one STL; most slicers can split them with an auto-arrange or split-to-parts command.
About GLB files
GLB is the binary container for glTF 2.0, the format the Khronos Group describes as the JPEG of 3D. One .glb file bundles a JSON scene description, binary mesh buffers and embedded images, so nothing can go missing in transit. The format was designed for efficient delivery and loading on the web, and it is now used by Three.js, Babylon.js, model-viewer, Google Search 3D results, Meta platforms, Unity and Unreal importers, and many marketplaces such as Sketchfab. glTF defines a physically based metallic-roughness material model, a node hierarchy, cameras, skins and animations. Coordinates are in metres with +Y up and a right-handed system. It is excellent for display and game assets, but it is a presentation format rather than a manufacturing one, so print workflows usually convert it first.
About STL files
STL was created by 3D Systems in the late 1980s for its stereolithography machines, and it became the default exchange format for 3D printing. A file describes a surface as a list of triangles, each with three vertices and a facet normal. That is all it contains. There is no header field for units, no colour, no texture and no notion of separate parts. Two flavours exist: ASCII, which is readable text but large, and binary, which spends exactly 50 bytes per triangle after an 80-byte header and a 4-byte triangle count. Binary is what almost every modern tool writes. Because the format is so small and so old, every slicer, CAD package and mesh editor can read it, which is why hobbyists still download most printable models as STL from sites like Printables and Thingiverse.
3D printing notes
STL is still the safest file to hand to a slicer. Bambu Studio, PrusaSlicer, OrcaSlicer, Cura and the resin tools Chitubox and Lychee all import it, and they all treat the numbers as millimetres. The usual problems are scale (a model exported from a metre-based tool arrives 1000 times too small) and meshes that are not watertight, which makes slicers fill or skip regions. MeshShift shows the real dimensions before you convert and can scale from metres automatically. Its print check lists holes, non-manifold edges and flipped normals, and one click rebuilds a closed solid at the same size. If you need colours or several plates in one file, use 3MF instead.
Frequently asked questions
Why is my converted STL tiny or huge?
GLB is defined in metres, STL is read as millimetres. MeshShift multiplies by 1000 by default. If the source was authored in other units, turn the scale option off and set the size you want.
Is a GLB from an AI generator ready to print?
Often not. These meshes can have holes, thin shells and no flat base. Convert to STL, run the print check and repair, and look at the overhang highlight in the viewer before slicing.
Is this GLB to STL converter free and private?
Yes. The conversion runs in your browser with JavaScript and WebAssembly, so your GLB file is never uploaded to a server. There is no sign-up, no watermark and no daily limit; very large files are limited only by your device's memory.