3DTILES_content_gltf

⚠️ 3DTILES_content_gltf has been promoted to core in 3D Tiles 1.1. See glTF Tile Format. ⚠️

3DTILES_content_gltf

Contributors

• Sean Lilley, Cesium
• Peter Gagliardi, Cesium
• Marco Hutter, Cesium
• Don McCurdy, Independent
• Patrick Cozzi, Cesium

Status

Complete

Dependencies

Written against the 3D Tiles 1.0 specification.

Optional vs. Required

This extension is required, meaning it must be placed in both the extensionsUsed and extensionsRequired lists in the tileset JSON.

Overview

This extension allows a tileset to use glTF 2.0 assets directly as tile content. Both glTF JSON and GLB binary formats are supported.

Using glTF as a tile format simplifies content pipelines from creation to runtime. This allows greater compatibility with existing tools (e.g. 3D modeling software, validators, optimizers) that create or process glTF assets. Runtime engines that currently support glTF can more easily support 3D Tiles. In many cases, existing tile formats can be converted into the corresponding glTF content, as described in the Migration Guide.

Extension JSON

Defined in tileset.3DTILES_content_gltf.schema.json.

With this extension, the tile content may be a glTF asset. Runtime engines must be able to determine compatibility before loading the content. If the glTF asset uses or requires certain glTF extensions, then these extensions must also be listed in the 3DTILES_content_gltf object. This is a property of the top-level tileset extensions object with the following properties:

• extensionsUsed: an array of glTF extensions used by any glTF content in the tileset.
• extensionsRequired: an array of glTF extensions required by any glTF content in the tileset.

Example: A tileset that uses the 3DTILES_content_gltf extension to directly refer to a glTF asset in the content of the root tile. The glTF asset in turn requires the EXT_mesh_gpu_instancing extension.

{
  "asset": {
    "version": "1.0"
  },
  "extensionsUsed": ["3DTILES_content_gltf"],
  "extensionsRequired": ["3DTILES_content_gltf"],
  "extensions": {
    "3DTILES_content_gltf": {
      "extensionsUsed": ["EXT_mesh_gpu_instancing"],
      "extensionsRequired": ["EXT_mesh_gpu_instancing"]
    }
  },
  "geometricError": 240,
  "root": {
    "boundingVolume": {
      "region": [
        -1.3197209591796106,
        0.6988424218,
        -1.3196390408203893,
        0.6989055782,
        0,
        88
      ]
    },
    "geometricError": 0,
    "refine": "ADD",
    "content": {
      "uri": "trees.gltf"
    }
  }
}