Used to generically return an object that is inheriting from S3dItem Entity given an OID, regardless of the object class. For example:
GET https://MyServer.Domain.com/s3d/v1/Sites('MySiteAlias')/Plants('MyPlant')/S3dItems('{00004E2E-0000-0000-3B0E-272AE4542704}')
S3dItems collection cannot be used without an OID.