Aircraft Lights move wrt Aircraft during turning

For topics related to the creation of simulation objects (SimObjects). This includes development of aircraft, ground, and maritime vehicles.
FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Fri Mar 25, 2011 6:50 am

This bug has frustarted me for years, maybe Lockheed can fix it ..



A light .fx placed on an aircraft in aircrft.cfg, moves relative to the aircraft, as the aircraft turns through 360 degress, the amount of movement being proportional to the distance the plane is from lat N60.



At N60, there is no movement as the plane rotates in direction.



At other latitudes, it is very apparent, and can often make the light dissapear inside the aircraft, and thus become unobservable from outside the aircraft -- not good for Nav Lights !!



Placing the lights a sufficient distance OUTSIDE of the aircraft to stop this happening at all Latitudes needs a very significant displacement from the correct light poistion, and is really an unsatisfactoty fudge solution.



A picture is worth 1000 words, a Video worth even more.



Below is a link to a Video of a plane, at N25, taxiing in a circle, showing its Nav lights on its wing, moving wrt the wing, during the rotation.

( Nothing to do with wing flexing -- it would appear to be a lat/long calculation error or lack of precision rounding error of some sort.)



Not sure is the issue is cause by the LIGHT, or WING MODEL being in incorrect position... but the effect is very apparent.



http://fs-mp.com/p3d_forum/fx_lights.avi (50 meg avi)



Geoff










FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Fri Mar 25, 2011 2:43 pm

The movent I am talking about seems to be caused by errors in simulation calculating where to place the light in Lat.Long space, relative to the aircraft's center ref.



If you place lights on your bike, with the .CFG, they should not remain stationary when you lean. Leaning is like banking in the plane, the lights stay with the banked wing.



I think what I demonstrated in the video, is an issue with the X,Y to Latitude, Longitude calculations,.. either a miscalculation, inaccurate approximation to the transform, or a lack of precision in the calculation.



What is interesting is that the MIN.max movement points, do not occur at 0, 90, 180, 270 or even at 45, 135, 225, 315. They seem to occur at 60 degs from North, ie 60, 150, 240, 330. Really strange !!



Of course, the bigger the wingspan, the bigger the movement.

The example was on a small Ga Beechcraft Duke ( well spotted)

On a 747, or those Monster Russian Planes, the light movement is way more !



Waiting to see what the Lockheed GURUs have to say .... :)



Geoff






FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Fri Mar 25, 2011 6:47 pm

Makes sense. How about a 2 contact point bike, with animated rider legs that go down to ground when bike is very slow/stopped. Otherwise, a balacing" routine, to keep the bike stable, on its two contact points, when moving ... CHALLENGE !!! lol



Geoff



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