This tool is designed to place the ceiling elements automatically (Lighting fixture, Air Terminal, Sprinklers, Fire Alarm, and Data Devices) 

It will save a huge amount of time used to place lighting fixtures or air terminals....etc in the project.

The tool will work with hosted and none hosted families.

The tool will work with regular and irregular spaces.

The tool will place the elements at ceiling whether the ceiling exist in your model or the ceiling is exist at the linked file.