About tracks

[Moxica]

I don't have any problems, but I'm just curious:
Are tracks rendered in real time during playback?
If so, how can they diagnose performance issues if played on a different rig?
How are they useful, when they dont play the same as the actual mission/flight?
(One of my tracks had me landing on a totally different spot than actual flight, for example
Another had me chrashing into a tree right after takeoff, which did not happen during flight)

Edited May 25, 2023 by Moxica

[sthompson]

All reports I have read indicate that tracks do nothing more than record your inputs. Track playback then repeats the inputs. Obviously small differences in timing and/or in capture of inputs can lead to a large cumulative error even when played back on the same system as the one where the track was recorded. It's a known problem with track files. They work only for simple, short flights.

Ironically, tracks worked much better in DCS predecessor software such as Flanker. Presumably lower polling rates for the inputs explain this. However even in those legacy systems even small updates to the simulation software (e.g. tweak to a flight model) would break existing track files because a given set of inputs would then have different implied outcomes in the simulation.

I suspect the evolution of multi-threading will break track files further. Suppose for example that the polling of inputs occurs in a different thread from (and thus partially out of sync from) modeling of AI behavior. That will lead to further problems with the timing of inputs no longer matching up with other elements of the game during playback.  The whole system probably will need to be rewritten from scratch, or else scrapped. It worked well in legacy systems (which answers the question of why it exists even though it doesn't work well), but it is basically useless today except perhaps to show bugs in very short, artificial demonstrations.

 

Edited May 25, 2023 by sthompson
Added additional thoughts

[Rudel_chw]

1 hour ago, sthompson said:

tracks do nothing more than record your inputs.

 

Actually, the track also contains a copy of the mission file, this makes it easier to reproduce a reported issue and you can tell if the mission included any user mod.

[sthompson]

1 hour ago, Rudel_chw said:

 

Actually, the track also contains a copy of the mission file, this makes it easier to reproduce a reported issue and you can tell if the mission included any user mod.

Good point. And that explains why they are sometimes too large to upload to the forums for even a short flight.

[Moxica]

2 hours ago, Rudel_chw said:

 

Actually, the track also contains a copy of the mission file, this makes it easier to reproduce a reported issue and you can tell if the mission included any user mod.

In that case, it should be enough to link to the mission, if it is downloaded from the user files section. Or if it is one of the default ones.

[Rudel_chw]

52 minutes ago, Moxica said:

it should be enough to link to the mission

 

Many users run DCS using their own custom missions, not necesarily available on the web.

[Exorcet]

6 hours ago, Moxica said:

I don't have any problems, but I'm just curious:
Are tracks rendered in real time during playback?

Yes, the run in the sim engine based on your inputs and use seeds for random events.

6 hours ago, Moxica said:

If so, how can they diagnose performance issues if played on a different rig?

The track should play the same on any computer. While DCS tracks are bugged, not all of them break.

6 hours ago, Moxica said:

How are they useful, when they dont play the same as the actual mission/flight?

They do play out the same, sometimes. In the cases where they don't inputs can still be useful, and some idea of what happened can still be gained from an incorrect track.

 

[Moxica]

17 minutes ago, Rudel_chw said:

 

Many users run DCS using their own custom missions, not necesarily available on the web.

Orly?

[AKULA_OPTIMUS]

21 hours ago, Moxica said:

(One of my tracks had me landing on a totally different spot than actual flight, for example
Another had me chrashing into a tree right after takeoff, which did not happen during flight)

 

Did you use time acceleration during those flights? Because that always breaks the tracks (although they are already broken by deafult) 

[Moxica]

4 hours ago, AKULA_OPTIMUS said:

Did you use time acceleration during those flights? Because that always breaks the tracks (although they are already broken by deafult) 

Nope. They just played it wrong. Very strange, because it was my first landing in a tight spot with AH-64, and the replay landed on the other side of the road with plenty of space. 

[Ironhand]

3 hours ago, Moxica said:

…Very strange, because it was my first landing in a tight spot with AH-64, and the replay landed on the other side of the road with plenty of space. 

It landed? So it got it half right…