Originally posted by **balazsdukai** November 21, 2023
Geometries are not obligatory for CityObjects, so we have three valid options:
- `{ "type": "Building" }`
- `{ "type": "Building", "geometries": [ ] }`
- `{ "type": "Building", "geometries": [ ... ] }`
Then, a `Geometry` object must have a `"boundaries"` member with an array of vertex indices. But the specs does not explicitly allow or forbid empty arrays, such as `"boundaries": [ ]`.
In my opinion, it does not make much sense to have a Geometry object with empty boundaries, but it can happen. For instance due to a failed procedure that creates the geometry.
Should we consider an empty `boundaries` a valid or invalid CityJSON?
Discussed in https://github.com/cityjson/specs/discussions/188