3D file format guide

GLB vs glTF vs OBJ vs USDZ

Q: What is the difference between GLB and glTF?

glTF is the open Khronos standard; the .gltf variant is human-readable JSON that references external .bin and image files. GLB is the same data packaged as a single binary file. Because plain .gltf needs every referenced file present, GLB is preferred for distribution and drag-and-drop.

The four formats you'll meet most often in web and AR. Short version: use GLB for the web and Android AR, USDZ for native iOS AR, treat glTF as the underlying standard GLB packages, and treat OBJ as a legacy interchange format to convert from.

At-a-glance comparison

Format	What it is	Packs textures?	Android AR	iOS AR	Web 3D	Typical size
GLB	Binary glTF — one self-contained file	Yes (embedded)	Yes (Scene Viewer)	No (needs USDZ)	Yes	Small–medium
glTF (.gltf)	JSON scene + external .bin & textures	No (external files)	Yes (if assets resolve)	No (needs USDZ)	Yes	Small (multi-file)
OBJ	Legacy text mesh + optional .mtl	No (separate .mtl/maps)	Convert first	Convert first	Via conversion	Large (text)
USDZ	Apple's AR package (USD zipped)	Yes (embedded)	Not native	Yes (Quick Look)	Limited	Small–medium

"Convert first" means the format must be converted (for example OBJ → GLB, as the viewer here does in-browser) before AR.

GLB — the web/AR default

GLB is the binary form of glTF: a single file that bundles geometry, materials, animations, and textures together. Because it is self-contained, it is the easiest format to drag-and-drop, host, and pass to a viewer. It powers Android AR through Scene Viewer and is the standard input for Google's <model-viewer>. If you only keep one format, keep GLB.

glTF — the standard underneath

glTF ("GL Transmission Format") is an open Khronos standard sometimes called "the JPEG of 3D." The .gltf variant is human-readable JSON that references external binary (.bin) and image files. That multi-file nature makes plain .gltf awkward to drag-and-drop, since the loader needs every referenced file. For distribution, the same data is almost always shipped as a single GLB.

OBJ — legacy interchange

OBJ is an old, widely supported text format for mesh geometry, with materials in a companion .mtl file and textures as separate images. It has no animation support and no AR support of its own, and its text encoding makes files large. It is still common as an export/interchange format, which is why the viewer here converts OBJ to GLB in the browser before display.

USDZ — native iOS AR

USDZ is Apple's AR delivery format — a zipped package built on Pixar's Universal Scene Description. It is what iOS Quick Look uses to place models in the real world from Safari. The catch for a browser tool: USDZ generally cannot be generated in-browser from an arbitrary GLB, so client-side tools (including this one) provide interactive 3D on iOS rather than native Quick Look AR. Production pipelines such as WEARFITS export both GLB and USDZ so that AR is automatic on both platforms.

Quick recommendations

Embedding a product on the web + Android AR: ship GLB.
Native AR on iPhone/iPad: also ship USDZ alongside the GLB.
You were handed an OBJ: convert it to GLB (do it in the viewer).
Authoring/exporting from a 3D tool: export GLB; keep .gltf only if you need to edit the JSON.

Once you've picked a format, make sure the file is actually fast to load — see the guide to optimizing 3D models for web & AR for polygon budgets, Draco/meshopt compression, and KTX2 textures.

Last updated June 2026 · Photo-to-3D AR Viewer editorial

Frequently asked questions

Which 3D format should I use for the web and AR?

Use GLB. It is the binary form of glTF that bundles geometry, materials, animations, and textures into one self-contained file, loads directly in Google's <model-viewer>, and powers Android AR through Scene Viewer. If you only keep one format, keep GLB.

What is the difference between GLB and glTF?

glTF is the open Khronos standard; the .gltf variant is human-readable JSON that references external .bin and image files. GLB is the same data packaged as a single binary file. Because plain .gltf needs every referenced file present, GLB is preferred for distribution and drag-and-drop.

Can I use AR on iPhone with a GLB file?

Native iOS AR uses Quick Look, which needs a USDZ file rather than a GLB. USDZ generally cannot be generated in-browser from an arbitrary GLB, so client-side tools show interactive 3D on iOS. Production pipelines such as WEARFITS export both GLB and USDZ so AR is automatic on Android and iOS.

What should I do if I was handed an OBJ file?

OBJ is a legacy text mesh format with no animation or AR support of its own, and its text encoding makes files large. Convert it to GLB before use — the viewer on this site converts OBJ to GLB in the browser using three.js.