I've setup an AE project using a standard simple camera rig for extra control - using a series of parented nulls with sliders to control each cam move - one for bank, one for pitch, heading, tracking etc. I've then split X,Y & Z pos on the main controls null for cam tracking.
This works great for all my 3D layers and for Particular, but Horizon doesn't seem to be reacting to the tracking and 3 x position controls. All my other 3D layers move as expected, but only the X, Y & Z *rotation* controls are doing anything for Horizon.
Any ideas if this is right or if I can adapt my rig to gain full control of my Horizon BG?
Horizon is actually only concerned with the rotation of the camera as it is a spherical projection. Moving or translating position in the x y z space does not affect the orientation of the camera towards the spherical map, therefore, nothing will change. Think of the Horizon layer as infinately away from the camera so that there is no paralax, very similar to a starfield (unless you are moving very very fast). So, if I understand what you are asking, it is impossible. What you can do to fake it is to put 3d layers far from the camera to create a layer of paralax between your foreground objects and the background to sell the 3d world.