I hope this doesn't sound silly but what actually moves in FSX.Does the engine render a moving plane, and static scenery,or is the airplane static while the scenery is moving.In short, how does FSX create the illusion of movement?Cheers.

Nothing 'moves' Dimi - only programmed electrons...http://www.wisegeek.com/what-is-a-lcd-monitor.htm

We know ACES themselves that the plane is still and the scenery moves toward the plane.

In a similar discussion a fellow named Einstein said it was all relative......

Very true Paul!!Or maybe as quantum physicists like to say,"Nothing is Real"

So which ever moves would that not effect the little cars on the road? So does the road move and the car stays still while the scenery or the plane is moving? Sounds pretty confusing.Bob

Same here.How is the illusion of movement created?

in the case of cars/boats, I would say that the AI moves, you can sit an an airport and not have any scenery moving yet see the ai stuff move, so.. ai moves.now as to weather or not the a/c vs scenery moves?

The plane is stationary and everything moves away or towards you.

User is static - sitting in easy chair in front of monitor.Monitor is static - placed on table or other furniture.FS display is modified - pixels change as viewpoint (aircraft) follows commands of joystick and/or throttle.Joystick and/or throttle is static - sitting on lap or furniture.Earth is moving - rotating at about 900 knots, faster than your average C182 or your easy chair.Earth is moving - around the sun at about 107,218 km/h (for the metrically challenged, that is approximately 66,622 mph).Solar System is moving - around the center of the galaxy at about 828,000 km/h - 514,495 mph.Galaxy is moving - expanding from the center of the universe, wherever that may be, at about 1,987,200 km/h - 1,234,789 mph.Difficult to add all these speeds together since they don't all have the same vector at the same time, but it may be somewhere in the vicinity of Mach 2000.Isn't life wonderful? Sorry, the word is "awesome, dude!"Best regards.Luis

Great post, Luis.

Nice post Luis!Jim that makes sense, but I am no closer in understanding the illusion of movement witthin the sim.

Aircraft move relative to the world. The Simulation Variables include velcities and accelarations in body and world coordinates:VELOCITY BODY Z True longitudinal speed, relative to aircraft axisVELOCITY WORLD Z Speed relative to earth, in North/South directionACCELERATION BODY Z Acceleration relative to aircraft axis, in north/south directionACCELERATION WORLD Z Acceleration relative to earth, in north/south direction

...the illusion of movement witthin the sim...

...is just that, an illusion.If you look at each individual frame of an old fashion film strip movie there is no movement.If you tape them together and run them past a light source, projected on a wall, you see the illusion of movement.regards,Joe

My assumption would be:Everything in the sim has a state vector and is located in 3d space x-y-z defined by lat long and alt, and oriented by pbh (pitch, bank, heading). In addition there are 6 axis of velocity and acceleration (3 translational and 3 rotational), Every time the main sim loop is run the state vector is recomputed. Separately, a view is computed, with an origin in xyz and with pbh orientation vector. In most cases the xyz and pbh are computed by adding an offset to some other xyz/pbh (for example, tower position or aircraft center. I assume that scenery objects are simplified in that their state vector does not include velocity or acceleration, as the reference frame is earth-centered.scott s..