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Visual jittering

Connecting two computers, using generic protocol, connecting with Matlab?

Visual jittering

Postby metow » Tue May 12, 2020 9:44 pm

Hello,
Im using generic protocol to visualize my own fdm.
So far i have set --fdm=null, prepared an xml file to define variables that i set.

Im only sending lat,lon,alt info as well as euler angles and heading values and its working. However the visual is jitterring especially when i am close to ground. I see buildings shaking and it disturbs me a lot. I dont think it is related with my hadrware since flight gears built-in fdm works smoothly when i delete --fdm=null.

Im sending data to udp port at a rate of 40hz. Though which i also tried 20,30,100,125 hz which all seemed to improve nothing at all.

Is jittering because i should rather be using native protocol? Is it faster for fg to interpret?

Im a bit lost here, any kind of help would help
metow
 
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Re: Visual jittering

Postby jano » Sat May 16, 2020 12:07 am

It's something quite simple, the way FG works with external fdm is quite crude, it simply use the last position it received as plane's position, so sometimes the plane stay inplace for some frame, and in other case, FG don't use time information, so you loose the smooth steady speed of the plane having something jumpy.

you can try using max frame rate setting in FG and kind of syncing your fps to the sending rate, but i'm not sure this will work much better.

With the actual FG, a way to have a smooth plane would be sending the position as mp packet, as the mp planes use time informations, or improve the generic protocol :)

hope this help !
jano
 
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