Eyepoint Data P:var lagging

AlexisVGR
Posts: 37
Joined: Wed Jan 18, 2012 8:23 am

Eyepoint Data P:var lagging

Postby AlexisVGR » Thu Sep 05, 2019 12:07 pm

Hello,

I am trying to create an Eyepoint position tracker that takes the Lat/Long/Alt A:vars and eyepoint Lat/Long/Alt P:vars and transforms these into aircraft-origin relative X-Y-Z. I know the aircraft's actual eyepoint position from the source model and use this as reference.

So far I have succeeded in doing the required transformations that will convert the eyepoint from world/polar to aircraft/cartesian and it works for all plane attitudes while in slew mode.

When I exit slew mode and any form of speed is present, the solution lags behind the actual eyepoint by a big margin (1m or more).

If I'm in straight and level flight, the eyepoint's longitudinal offset will be off. The faster I fly, the more off it goes.
Similarly, when rolling, yawing or crabbing, the eyepoint calculation lags a couple of frames behind the actual position.

While I can compensate for the delay by calculating the difference in speed between updates, I believe that it could be a bug in the P:vars The calculation seems to work properly when the plane is still, but veers off as speeds increase, I suspect that the eyepoint P:vars aren't synchronised properly with the A:vars, resulting in this offset.
SimWorks Studios
Alex Vletsas
3D Modeler & Animator
http://www.facebook.com/SimWorksStudios

obinder
Posts: 124
Joined: Sun Jun 08, 2014 9:43 am

Re: Eyepoint Data P:var lagging

Postby obinder » Thu Sep 05, 2019 1:47 pm

Hello,

since you have posted this in the SimConnect section, a question comes to mind: why are you not using the View Functions provided by the API?

For example, "RequestCameraRelative6DOF" will give you the x/y/z/p/b/h offsets relative to the eyepoint of the aircraft.

Best regards
Oliver Binder
Lorby-SI

AlexisVGR
Posts: 37
Joined: Wed Jan 18, 2012 8:23 am

Re: Eyepoint Data P:var lagging

Postby AlexisVGR » Fri Sep 06, 2019 8:50 am

That is one suggestion worth trying, thanks Oliver!

Still, I'd like to know whether the P:vars do lag indeed.
SimWorks Studios
Alex Vletsas
3D Modeler & Animator
http://www.facebook.com/SimWorksStudios

obinder
Posts: 124
Joined: Sun Jun 08, 2014 9:43 am

Re: Eyepoint Data P:var lagging

Postby obinder » Fri Sep 06, 2019 9:02 am

That is one suggestion worth trying, thanks Oliver!

Still, I'd like to know whether the P:vars do lag indeed.
In my experience, the lag can have multiple causes. One is the FPS setting. Unlimited FPS often lead to lags and stuttering when your code is not clocked at exactly the same update rate. Or it could be computational lag, a gauge for example is only updated every 55ms by default. Depending on when exactly values are read and then displayed, there may be a discrepancy. That your lag is getting bigger at higher speed points to something like that. Of course, the computational lag can be in P3D itself too.

Best regards
Oliver Binder
Lorby-SI

parmstro_nasa
Posts: 1
Joined: Thu Oct 17, 2019 6:05 pm

Re: Eyepoint Data P:var lagging

Postby parmstro_nasa » Sat Nov 02, 2019 9:52 pm

@AlexisVGR, did you solve this problem? I am having the same issue, my eye tracking lags behind the aircraft when any appreciable speed is present. Though when the aircraft is stationary the eye tracking is good. I slowed my frame rate to 15 fps but that did not solve the problem.


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