GLB vs USDZ: which 3D format do you need for AR?

GLB in one paragraph

GLB is the binary form of glTF 2.0, an open standard from the Khronos Group, the body behind OpenGL and Vulkan. One GLB file carries the geometry, the materials, the textures and any animation, so it travels as a single file. Web 3D viewers read it natively, and Android's own AR viewer opens it directly. It is often called "the JPEG of 3D" for that reason: small, complete and understood everywhere on the web.

USDZ in one paragraph

USDZ is a packaged form of USD, the scene format Pixar created and Apple adopted for AR. It is the format AR Quick Look reads, the viewer built into iPhone and iPad. When an iPhone shopper taps "View in AR" on a web page, the file that opens is a USDZ.

The differences that matter to a store

• Where it opens. GLB: web 3D viewers and Android AR. USDZ: AR on iPhone and iPad.
• Who makes it. Almost every 3D tool exports GLB, including Blender for free. USDZ is usually converted from another file rather than modelled directly.
• Materials. Both use physically based materials (base colour, metalness, roughness, normal maps), so a product that looks right in one can look right in the other. Glass, transparency and special effects are where they diverge most, so check those products on both systems.
• Units. glTF counts in metres. USD can use other units and declares which one. A model exported at the wrong scale is the most common reason a sofa appears the size of a toy in AR.

Do you need both?

A web store that wants AR on both iPhone and Android needs both formats in the end, but it rarely needs to author both. The usual path is one master GLB, from which the USDZ is produced automatically.

That is how Custivo works: the viewer reads GLB and USDZ directly, and when you upload a GLB, the USDZ that iPhone AR needs is produced from it. If you already have only a USDZ, that works too. The one file to insist on when you order a model is a clean GLB.

Five checks before a model goes live

1. Real-world scale. Measure one dimension in the model and compare it with the product sheet. AR shows the product at the size the file says, not the size it really is.
2. The origin on the floor. The model's origin point should sit at the base of the product, or it will float or sink in AR.
3. Texture size. Textures, not polygons, make most files heavy. On a phone, 2048 pixels per texture is plenty for most products.
4. Transparent and glass parts. Open them on an iPhone and an Android phone. These are the materials the two systems draw differently.
5. The file size. A few megabytes loads quickly on a phone connection; tens of megabytes do not. An optimizer brings a heavy source file down without redrawing the product. Custivo has one in the scene editor, a click away from the model you uploaded.

If your file is FBX, OBJ or CAD

Suppliers often send FBX, OBJ, STEP or other CAD formats. Blender can open most of them and export a GLB (File, Export, glTF 2.0). CAD files usually need their surfaces converted to a mesh first, and their hidden internal parts removed, or the file will be far heavier than the product needs.

If a file cannot be rescued, it is usually faster to model the product again. You can also scan it with the Custivo app on an iPhone, or have our 3D team model it for a quoted price.