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defaultGeometrySchema.cmn.md

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defaultGeometrySchema [common profiles]

The defaultGeometry schema is used in stores where all arrayBufferView geometry declarations use the same pattern for face and vertex elements. This schema reduces redundancies of arrayBufferView geometry declarations in a store and reuses the geometryAttribute type from featureData. Only valueType and valuesPerElement are required.

Geometry buffer

fieldName type description
vertexCount UINT32 Number of vertices
featureCount UINT32 Number of features.
position Float32[3*vertex count] Vertex x,y,z positions.
normal Float32[3*vertex count] Normals x,y,z vectors.
uv0 Float32[2*vertex count] Texture coordinates.
color UInt8[4*vertex count RGBA colors.
id UInt64[feature count] Feature IDs.
faceRange UInt32[2*feature count Inclusive range of the mesh triangles belonging to each feature in the featureID array.
region UINT16[4*vertex count] UV region for repeated textures.

Related:

cmn::store, psl::store

Properties

Property Type Description
geometryType string Low-level default geometry type. If defined, all geometries in the store are expected to have this type.
Must be:
  • triangles
topology string Declares the topology of embedded geometry attributes. When 'Indexed', the indices must also be declared in the geometry schema ('faces') and precede the vertexAttribute data.
Possible values are:
  • PerAttributeArray
  • Indexed: When Indexed, the indices must also be declared in the geometry schema (faces) and precede the vertexAttribute data.
header headerAttribute[] Defines header fields in the geometry resources of this store that precede the vertex (and index) data.
ordering string[] Defines the ordering of the vertex Attributes.
vertexAttributes vertexAttribute Declaration of the attributes per vertex in the geometry, such as position, normals or texture coordinates.
faces vertexAttribute Declaration of the indices into vertex attributes that define faces in the geometry, such as position, normals or texture coordinates.
featureAttributeOrder string[] Provides the order of the keys in featureAttributes, if present.
featureAttributes featureAttribute Declaration of the attributes per feature in the geometry, such as feature ID or face range.

Note: properties in bold are required

Examples

Example: defaultGeometrySchema for 3D Object and integrated mesh scene layer

 {
  "geometryType": "triangles",
  "header": [
    {
      "property": "vertexCount",
      "type": "UInt32"
    },
    {
      "property": "featureCount",
      "type": "UInt32"
    }
  ],
  "topology": "PerAttributeArray",
  "ordering": [
    "position",
    "normal",
    "uv0",
    "color"
  ],
  "vertexAttributes": {
    "position": {
      "valueType": "Float32",
      "valuesPerElement": 3
    },
    "normal": {
      "valueType": "Float32",
      "valuesPerElement": 3
    },
    "uv0": {
      "valueType": "Float32",
      "valuesPerElement": 2
    },
    "color": {
      "valueType": "UInt8",
      "valuesPerElement": 4
    }
  },
  "featureAttributeOrder": [
    "id",
    "faceRange"
  ],
  "featureAttributes": {
    "id": {
      "valueType": "UInt64",
      "valuesPerElement": 1
    },
    "faceRange": {
      "valueType": "UInt32",
      "valuesPerElement": 2
    }
  }
}