GLB vs glTF vs OBJ vs STL — Which 3D Format Should You Use?

You exported a 3D model and now you’re staring at a dropdown asking for GLB, glTF, OBJ, or STL — and they all sound the same. They’re not. Pick the wrong one and you’ll lose your textures, your animation, or your colour. Here’s what each format actually stores, and a simple rule for choosing.

The 30-second answer

Format	Keeps	Best for
GLB	Meshes, PBR materials, textures, rigging, animation — all in one file	Web, AR, sharing, real-time
glTF	Same as GLB, but split into `.gltf` + `.bin` + texture files	Web pipelines where you edit assets separately
OBJ	Geometry, normals, UVs (materials via a separate `.mtl`)	Simple, static models; wide app support
STL	Geometry only — bare triangles, no colour or UVs	3D printing

If you’re not sure, GLB is the safest modern default: it keeps everything and travels as a single file.

glTF and GLB — the “JPEG of 3D”

glTF (GL Transmission Format) is a modern standard from the Khronos Group, designed for delivering 3D efficiently to real-time engines, browsers and AR. It’s the format behind most “view in your space” AR features and almost every 3D model you rotate on a web page.

It’s the most complete of the four. A glTF file can carry:

meshes and the full scene graph (how parts are arranged),
PBR materials (physically-based — the modern lighting model) and textures,
rigging (skeletons) and animations,
cameras and lights.

The only difference between the two flavours:

.gltf is JSON, and usually references separate files — a .bin for geometry and image files for textures. Handy when you want to tweak textures independently.
.glb packs all of that — JSON, geometry and textures — into one binary file. Nothing to lose track of, so it’s the best choice for sharing or shipping.

glTF also supports Draco compression, which can shrink a heavy mesh dramatically — often 5–10× smaller — with no visible quality loss. If your GLB is large, that’s the first knob to turn.

OBJ — the old, universal workhorse

Wavefront OBJ has been around since the late 1980s, and almost every 3D app can read it. It stores geometry, normals and UV coordinates as plain text. Materials aren’t inside the OBJ itself — they live in a companion .mtl file, and that material model is basic (not PBR).

What OBJ can’t do: rigging or animation. There’s no skeleton, no keyframes. So OBJ is great for a single static prop you want maximum compatibility for, and a poor choice for anything that moves. Because it’s text, OBJ files are also verbose — a detailed mesh can get large.

STL — geometry only, made for 3D printing

STL is the lingua franca of 3D printing, and it’s deliberately minimal: it describes the surface as a big list of triangles and nothing else. No colours, no UVs, no materials, no rigging, no animation — not even proper per-vertex normals (only per-face).

That’s exactly what a slicer needs to print an object, which is why every printer and slicer speaks STL. But it also means STL is the wrong format for a textured or animated model — all of that is simply thrown away. Detailed STLs can also be huge, since there’s no compression and every triangle is stored explicitly.

Which should you use?

Putting a model on a website or into AR? → GLB. Complete, compact, one file.
Handing a model to a web team who’ll edit textures? → glTF (split files).
Maximum app compatibility for a static model? → OBJ.
3D printing? → STL (or .3mf if your slicer supports it).
Just want the smallest file for the web? → GLB with Draco compression.

Converting between them — in your browser

You don’t need heavyweight software to switch formats. Our 3D viewer & converter opens GLB, glTF, OBJ and STL, shows you the model plus its stats (meshes, vertices, materials, rigging, animations), and exports to any of the four — entirely in your browser, with nothing uploaded. It can also apply Draco compression to GLB output and tells you how much smaller the result is.

Just remember what each target format keeps: convert to STL and you’ll drop materials and animation; convert to OBJ and you’ll drop rigging and animation; convert to GLB/glTF and everything comes along.

FAQ

Is GLB better than glTF? They’re the same format — GLB is just the single-file binary packaging of glTF. Use GLB to share or ship; use .gltf when you want the textures and geometry as separate, editable files.

Can I convert STL to GLB to get colour back? No — STL never stored colour or materials, so converting it forward can’t invent them. You’d get the geometry only. Add materials in a 3D editor afterward.

Why is my STL file so large? STL stores every triangle with no compression. High-poly models balloon quickly. For the web, use GLB with Draco instead — it’s a fraction of the size.

Does the converter upload my model? No. Everything is parsed and converted locally in your browser with WebGL — your model never leaves your device.

Need to switch formats now? Drop your model into the 3D viewer & converter and export to GLB, glTF, OBJ or STL — no uploads, no installs. Working with 2D files too? The PDF and image tools run the same way: on your device, never on a server.