I am an architect looking to use a Phantom 4 to film our projects. I am wondering what the best 3rd party app would be for this kind of work. The two features I'm looking for are: - The ability to fly around while the camera stays focussed on a subject - The ability to fly indoors and pre-program the flight path and camera direction. This would be similar to the DJI Go app "way points" feature except the camera direction is also pre-programmed. What I don't require is the ability to track moving objects. Any advice would be greatly appreciated. Thanks!