This sample demonstrates usage of the EXT_structural_metadata extension for storing a property table with metadata that is looked up based on feature IDs.
The sample contains a glTF asset with a single mesh primitive. The mesh primitive consists of a quad (the unit square), formed by 2 triangles. The vertices in this mesh primitive have the usual POSITION, NORMAL, and TEXCOORD_0 vertex attributes.
The sample uses the EXT_mesh_features extension for storing feature IDs that are associated with the surface of a primitive, using a feature ID texture. The basic structure and definition of the feature IDs for this example is the same as for the FeatureIdTexture example.
Additionally, this sample defines metadata that is associated with the feature IDs.
The metadata in this example consists of a single example class inside an EXT_structural_metadata schema. The entities are the actual instances of this class, and are defined with an EXT_structural_metadata property table. The class defines a component property that contains STRING elements indicating the component of the building, and a yearBuilt property that contains INT16 elements, indicating the year when each component was built:
"component" : [
"Wall", "Door", "Roof", "Window"
],
"yearBuilt" : [
1960, 1996, 1985, 2002
]
This example can be viewed with the common sandcastle code.