Wrong componentType (too many vertices for uint8)

[julienduroure]

Hello,

In this file [0], the componentType of the indices accessor seems to be wrong.

problem_tile.glb

{
  "asset":{
    "version":"2.0",
    "generator":"draco_decoder",
    "copyright":"Google"
  },
  "scenes":[
    {
      "nodes":[
        0
      ]
    }
  ],
  "scene":0,
  "nodes":[
    {
      "mesh":0,
      "translation":[
        851227.05319905072,
        4379922.724366514,
        4543783.8765163999
      ]
    }
  ],
  "meshes":[
    {
      "primitives":[
        {
          "attributes":{
            "POSITION":1,
            "TEXCOORD_0":2
          },
          "indices":0,
          "mode":4,
          "material":0,
          "extensions":{
            "KHR_draco_mesh_compression":{
              "bufferView":0,
              "attributes":{
                "POSITION":0,
                "TEXCOORD_0":1
              }
            }
          }
        }
      ]
    }
  ],
  "accessors":[
    {
      "componentType":5121,
      "count":513,
      "type":"SCALAR"
    },
    {
      "componentType":5126,
      "count":314,
      "max":[
        53.494731903076172,
        37.779499053955078,
        -9.2874250411987305
      ],
      "min":[
        -69.238937377929688,
        -95.882095336914062,
        -92.276382446289062
      ],
      "type":"VEC3"
    },
    {
      "componentType":5126,
      "count":314,
      "type":"VEC2"
    }
  ],
  "materials":[
    {
      "pbrMetallicRoughness":{
        "baseColorTexture":{
          "index":0,
          "texCoord":0
        },
        "baseColorFactor":[
          1,
          1,
          1,
          1
        ],
        "metallicFactor":1,
        "roughnessFactor":1
      },
      "emissiveFactor":[
        0,
        0,
        0
      ],
      "alphaMode":"OPAQUE",
      "extensions":{
        "KHR_materials_unlit":{
          
        }
      }
    }
  ],
  "textures":[
    {
      "source":0,
      "sampler":0
    }
  ],
  "samplers":[
    {
      "wrapS":33071,
      "wrapT":33071
    }
  ],
  "images":[
    {
      "bufferView":1,
      "mimeType":"image/jpeg"
    }
  ],
  "bufferViews":[
    {
      "buffer":0,
      "byteOffset":0,
      "byteLength":1108
    },
    {
      "buffer":0,
      "byteOffset":1108,
      "byteLength":3108
    }
  ],
  "buffers":[
    {
      "byteLength":4216
    }
  ],
  "extensionsRequired":[
    "KHR_draco_mesh_compression",
    "KHR_materials_unlit"
  ],
  "extensionsUsed":[
    "KHR_draco_mesh_compression",
    "KHR_materials_unlit"
  ]
}

Not sure how this file was created, but it is coming from Google 3D Tiles (so, Draco is also from google, so I hope you will be able to retrieve the right team)

The file has 314 vertices, so indices can't be stored on uint8 / componentType 5121

Originally reported on Blender glTF I/O repo: [1]

[0] : https://github.com/KhronosGroup/glTF-Blender-IO/files/14599795/problem_tile.zip
[1] : KhronosGroup/glTF-Blender-IO#2162

[julienduroure]

Hello,
Any news on that?