Pre-Composing The Rooms
To get rid of the ugly double projection problem, we need to pre-compose the two rooms independently. Because the compositions for both rooms will contain some 3D elements (the walls, light and projection layer) and all 3D elements depend on a camera for correct positioning, we first need to duplicate the Camera and the Camera Null object. Ensure the copy of the camera is parented to the copy of the null object.
Select all layers we set up for room one, the connecting piece between the rooms, the copy of the camera and the copy of the Camera Null object and pre-compose them.
Call the composition ‘Room 1’.
Duplicate the camera and the Camera Null object one more time and ensure the copy of the camera is parented to the copied Camera Null layer.
Select all layers except for the ‘Room 2’ composition and pre-compose them. Call this comp ‘Room 2’.
Our final composition should have two nested compositions in it, Room 1 and Room 2, as well as a camera and the Camera Null layer as well as the concrete connecting piece between the rooms.
Playing through our animation, you will likely encounter some strange overlapping visual elements between the two rooms. Most of them will be caused by the fact that the 2 compositions we created for the rooms are flat layers and their 3D layers don’t know anything about each other and therefore won’t properly obscure each other.
This however, can be easily fixed by adding an animated mask to the room that sits on top and removing the overlapping artefacts. You may also have to tweak the connecting concrete piece a little bit to clean up the connection point :)
And with that you should be done with your complex – but very awesome – 3D transition effect!
I hope you enjoyed this tutorial and find lots of useful applications for this effect (or any variants of it) for your own projects :)