- GLB is a scene file: geometry plus materials, textures, and animation in one binary. Use it to publish or hand off a finished model.
- STL is geometry only — triangles with no colour, no material, and usually no units. Use it for slicers and 3D printing.
- OBJ is the interoperable middle ground: read by older DCC and CAD tools, with materials split into a separate
.mtl. - Converting is lossy in one direction only: going to STL throws away colour and texture, and nothing brings that back.
If you generated a model with an image-to-3D tool, you almost certainly received a GLB. Then something downstream — a slicer, a print shop, an older CAD seat — asked for STL or OBJ. This page is the decision table for that moment, plus the exact conversion path for each pair.
The one-line answer
| Question | Use | Because |
|---|---|---|
| Publish on the web, keep textures and animation | GLB | One binary carries mesh, PBR materials, and clip data; browsers and engines load it directly. |
| Slice for FDM or resin printing | STL | Slicers want a triangle soup with no materials to interpret; STL is the lowest common denominator. |
| Open in Blender, Maya, or older CAD | OBJ | OBJ has the widest reader support and survives round-trips through legacy pipelines. |
| Keep a master copy you can re-export from | GLB | Only GLB keeps the full look; treat STL and OBJ as disposable derivatives. |
What each format actually stores
GLB (glTF binary)
JSON scene description, binary mesh buffers, embedded textures, and animation. Modern, PBR-native, and the default output of most AI 3D generators.
STL
A flat list of triangles with a normal per facet. No colour, no material, no UVs, and typically no real-world unit — the slicer guesses or you set it.
OBJ
Vertices, UVs, and normals as plain text, with materials in a sibling .mtl file. Bulky, but easy to diff and easy for old tools to read.
The asymmetry that matters
GLB to STL and GLB to OBJ are lossy but safe: you still have the GLB if you keep it. STL to OBJ and STL to GLB are not restorations — there is no colour in an STL to restore, so the result is grey geometry. Always convert from the richest file you own.
Converting, pair by pair
GLB to STL
Open the free GLB to STL converter, drop the GLB, download the STL. It runs locally in your browser, so an unreleased model never leaves your machine.
GLB to OBJ
Use the GLB to OBJ converter when the next stop is Blender, Maya, or a CAD seat that will not read glTF. Expect the material to arrive as a separate .mtl.
STL to OBJ
Use STL to OBJ when a tool needs OBJ specifically. The mesh survives; colour does not exist in the source, so do not expect any.
OBJ to GLB
Use OBJ to GLB to bring a legacy asset into a modern pipeline. You get one portable file, but a classic OBJ has no PBR data to carry over.
Check before you ship
Open the result in the browser GLB inspector to confirm triangle count, bounding box, and — for GLB — that textures survived.
Browser-only, private
Free GLB to STL Converter
Convert GLB to STL locally for geometry-only 3D printing checks, slicers, and manufacturing review.
Free GLB to STL Converter
Runs locally in your browser, no upload. Load it to start.
Three mistakes that cost real time
- Exporting STL for a textured review. The reviewer sees grey clay and files a bug that is not a bug. Send GLB when the point is how it looks.
- Assuming STL has units. Most STL files are unitless. Confirm the bounding box in millimetres in the viewer and scale there, not in the slicer, where a wrong guess stays invisible until the first layer.
- Converting a converted file. STL to OBJ to GLB bakes in the loss twice. Always convert from the original GLB.
Frequently asked
Is GLB better than STL?
They answer different questions. GLB is better for anything visual — delivery, review, engines, the web. STL is better for anything mechanical — slicing, printing, and geometry-only exchange.
Can I convert STL back to GLB and get my textures back?
No. STL never stored them. If you still have the original GLB, convert from that instead; if you do not, the colour has to be re-authored.
Does converting cost Pixal3D credits?
No. Every converter and viewer on this site runs locally in your browser, so nothing is uploaded and no credits are spent. Credits only apply when you generate a new model on the Pixal3D AI 3D generator.
Next steps
If you are starting from a photo rather than an existing file, generate the GLB first on the AI 3D generator, then come back and export whichever format the next tool wants. To compare the two image-to-3D routes before you commit, read Pixal3D vs TRELLIS 2. For the full preparation checklist, see the Pixal3D image-to-3D guide.
Useful tools on this site: GLB to STL, GLB to OBJ, STL to OBJ, OBJ to GLB, STL viewer, and the GLB inspector.