Add a built-in variable for geometry type

[OmarShehata]

Currently it's possible to style features by ID:

tileset.style = new Cesium.Cesium3DTileStyle({
       color: {
           conditions: [
               ['${ID} >= "uniqueID"', 'rgba(45, 0, 75, 0.5)'],
               ['true', 'rgb(127, 59, 8)']
           ]
       }
   });

It would be nice to be able style by type. For example, you have a composite tile composed of vector tiles and b3dm, and you want to color only the lines in the vector tiles (a use case which came up on the forum). So something like this could work:

tileset.style = new Cesium.Cesium3DTileStyle({
       color: {
           conditions: [
               ['${TYPE} == "polyline"', 'rgba(45, 0, 75, 0.5)'],
               ['true', 'rgb(127, 59, 8)']
           ]
       }
   });

Currently I think the workaround would be to add your own type to the batch table and style based on that?

[donmccurdy]

Related:

• Declarative styling #2

Unless this becomes a built-in variable in declarative styling, I think the recommended solution would be to use an enum- or integer-typed property value in EXT_mesh_features. See 3D Tiles Next. No need for a custom metadata semantic in this case, since the property is just used for styling and not actually determining the geometry type.