Hi Tim 767,
The longitudinal arm of aircraft is drawn on the screen as a small cross
This cross is at the screen center in forward view with nothing (ctrl+w)
In forward view with 3D panel this cross moves vertically according the value "view center Y; panel view" in the menu Viewpoint --> Cockpit --> Screen-Centers of Plane Maker
Horizon is in relation with this cross according the pilot view pitch and roll, aircraft pitch and roll, zoom, ….
Modifing the value "view center Y", I may center the cross in forward view with 3D panel. (Position of the cross is directly proportionel) and therfore position an artificial horizon on the scrreen.
My inquiry is : How X-Plane is using this "view center Y" value ?
ptimib