Blog · How-to
How to convert GLB to STL for 3D printing
You found a great-looking GLB on Sketchfab, downloaded an AR model, or got one from a designer — and you want to print it. Every slicer (PrusaSlicer, Bambu Studio, Cura, OrcaSlicer) wants STL, 3MF or OBJ as input. None of them read GLB directly. Here's how to convert without losing the geometry.
Option 1 — Blender (free, reliable, all platforms)
The straightforward path.
- Install Blender from blender.org.
- Open Blender, delete the default cube (X).
- File → Import → glTF 2.0 (.glb/.gltf) → pick your file.
- The model imports with materials and animations — for printing you only need the mesh, but the import is non-destructive.
- Select all the imported meshes (A).
- File → Export → Stl (.stl).
- In the export dialog, tick "Selection Only" if you want just the selected meshes, "Apply Modifiers" if any are present. Pick binary format.
- Save.
That's it. The resulting STL has the geometry of the GLB, ready to slice.
Option 2 — glTF-Transform CLI
If you have Node.js installed:
npm install -g @gltf-transform/cli gltf-transform copy input.glb output.stl
One line, no GUI. Best for batch jobs.
Option 3 — online converters
Plenty of websites do it for free — upload, download. Don't use for confidential models. Common ones: Convertio, ImageToStl, Aspose, Anyconv.
What you lose in conversion
STL is a much simpler format than GLB. The conversion drops everything that's not geometry:
- Materials and textures — STL has no concept of colour.
- Animations — STL is static.
- Scene hierarchy — STL flattens everything into one triangle soup.
- Separate parts — multi-mesh GLBs collapse into one mesh.
For 3D printing, that's all fine — you only need geometry. For a multi-colour print on a Bambu A1, you'd want 3MF instead (it preserves per-mesh material assignment).
Common gotchas
The model is huge or tiny in the slicer
GLB usually uses metres as its unit, STL has no units but slicers default to millimetres. A 1 m tall character in GLB becomes a 1 mm sliver in the slicer if you don't scale. Fix: in Blender, before exporting STL, hit N to open the side panel and check Item → Dimensions. Set them to what you want in millimetres. Or scale in the slicer after import (Bambu, Prusa and Cura all show "scale to mm".)
The model has hollows or non-manifold geometry
GLBs from photogrammetry or AI generators often have small holes, internal walls or floating fragments. The slicer will try to print them anyway and might produce strange supports. Run the model through Blender's "3D Print Toolbox" addon (built in, just enable it) — it flags non-manifold edges and lets you fix them before exporting STL.
The mesh is too dense to print well
GLB models from Sketchfab or Quixel can have millions of triangles. Slicing converts to print instructions but doesn't reduce triangle count first, so big GLBs make slow slicers. In Blender: Modifiers → Decimate → set ratio to ~0.3, apply, then export. Halves the triangles, prints look identical.
The model is hollow at the bottom and won't print flat
Photogrammetry GLBs often have an open bottom. The slicer can usually auto-orient, but a closed bottom prints better. Easiest fix: in Blender, select the model, use Mesh → Snap → Selection to grid (or use the floor manipulator), then export.