glTF Viewer

The .gltf file is JSON. On its own it has no geometry: vertices live in a buffer, usually a .bin beside it, and materials point at image files. Select everything together:

scene.gltf
scene.bin
textures/basecolor.png
textures/normal.png

1. 1

   Select the group

   Drop the .gltf with its .bin and images, or press Open 3D file(s) and choose all of them. The JSON alone cannot be read into a scene.

2. 2

   Watch the dependency list

   The viewer reads the URIs before parsing. Files that are missing are named in Issues before a single triangle is built.

3. 3

   Inspect and save

   Overview, Materials and Animations describe the scene; Export PNG saves the current view.

Two arrays carry the dependencies. buffers[].uri names the .bin or uses a data: URI; images[].uri names a PNG or JPEG, uses a data: URI, or points at a buffer view inside a binary container.

Relative paths are resolved against the selected files, not against a folder on a server. A model keeps working after it moves, as long as its file names are still unique among the files that were selected with it.

• Missing buffer

  Fatal: without vertex data there is no model. The load stops, and the .bin the file expects is named in the message.

• Missing image

  The model opens and the material shows without that map. Issues lists each missing image by the path the file wrote.

• Two files with the same name

  Both are listed and neither is chosen. Opening the model again with one file of that name resolves it; the ambiguity is never settled by guessing.

• A path to another site

  Refused before any request is made. There is no remote fetch for model resources.

• A path with ..

  Refused as well: it would point outside the selected files, and there is no filesystem here to escape to.

extensionsRequired lists the extensions a reader must implement to open the file at all. extensionsUsed lists the ones the file benefits from. The viewer checks the required list first: an extension it does not implement stops the load, and the id is printed with the reason.

Draco geometry and meshopt buffers are implemented and decoded in the browser. KTX2 textures are not supported. Optional extensions that are not implemented are skipped, and the scene loads without that effect rather than failing.

The panels are the ones the GLB viewer uses. The difference is provenance: a texture slot can name an external file, show as embedded for a data: URI, or come from a buffer view in a binary file. The Materials panel says which of the three it is.

Animations lists clips with their names and durations, and plays the selected one. A glTF scene carries animation the same way a GLB does: as JSON plus sampler accessors.

glTF keeps the scene and its resources apart, which suits pipelines that share a .bin or regenerate textures without touching the scene. GLB packs everything into one file, which suits delivery.

The GLB viewer for packed single-file scenes covers the other side of the same choice.