fixed Possible solution for: "Weapons and sometimes aircraft flicker or derender."

[SspectrumM]

Several friends and I regularly play DCS in co-op missions. I don't have the exact date, but for the past month or two, we've all been experiencing the same issues (only in multiplayer).

• Flickering of other players' and AI's aircraft or weapons on their pylons.

• Some AI units become invisible or start rotating erratically.

• The game tends to freeze more frequently.

• Very long loading times when selecting an aircraft.

We all managed to fix the problems by clearing the DCS cache, you know, the FXO and Metashaders 2 folders found in the "DCS.openbeta" folder in User.

I understand that this is a common practice that helps fix various errors that can appear in DCS from time to time.

Some examples:
 

 

 

Edited December 23, 2024 by SspectrumM

[Biggus]

I'll test it.  I do this every patch as a habit though.  But at this point I'll do anything for a fix in the short term.

[MoleUK]

I might have reproduced the flicker in a short track, or it might be another type of flicker. If it is the same type of flicker, it's causes by having in excess of 100 air/ground units in your FOV with the LOD set to 1.0, at least in this particular track.

Needs to be replayed in 1080p, need to own F5.

disappearing F5 test 200.trk

Edited December 24, 2024 by MoleUK

[Biggus]

In my testing after today's patch, the bug remains and neither changing LOD nor clearing fxo and metashaders fixes the issue.

[Biggus]

As the old thread was closed, I'm adding a log for both client and server.  I sat in the F10 screen and ended up getting a better handled crash with logs this time.

dcs client.log dcs server.log

Edit:  Here's a clip from another mission where you can see when the freeze happens.

This is two F-14s shooting at a Flogger that stopped rendering about 10 or 15 minutes after the mission started.  You can hear audio freeze prior to video and I can still move the map for a moment or two.  I've added the client log for this mission too.

 

dcs client log for video freeze event.log

Edited December 28, 2024 by Biggus
More logs and video.

[Biggus]

The very talented guys behind Retribution have narrowed it down to an issue with uncontrolled aircraft.  When they become active, they sometimes start flickering and moving oddly and stop rendering, and when another unit interacts with them (shoots them down, for example), clients will freeze.  By setting all AI aircraft to warm starts or air starts, the bug doesn't seem to occur.

@BIGNEWY this is might be worth mentioning to your team.

 

[BIGNEWY]

13 minutes ago, Biggus said:

The very talented guys behind Retribution have narrowed it down to an issue with uncontrolled aircraft.  When they become active, they sometimes start flickering and moving oddly and stop rendering, and when another unit interacts with them (shoots them down, for example), clients will freeze.  By setting all AI aircraft to warm starts or air starts, the bug doesn't seem to occur.

@BIGNEWY this is might be worth mentioning to your team.

 

I believe we do have this reported already but I will mention it to the team. 

thank you 

[Raffson]

3 hours ago, BIGNEWY said:

I believe we do have this reported already but I will mention it to the team. 

thank you 

I'd like to elaborate a little further on Biggus' post so that we're all on the same page here. Afaict the issue starts manifesting itself with uncontrolled aircraft as Biggus mentioned, but the issue starts before activation/start of the group. It always starts with the aircraft rotating (not "flashing", afaict the "flashing" isn't causing any real issues) 180 degrees around its Y-axis (iirc X-axis is north/south, Z-axis is west/east & Y-axis is up/down) some axis (see video). This happens almost instantaneously and speeds up at some point, after which the rotation becomes so fast, the aircraft eventually disappears into thin air. Please note that at this point, the aircraft is still uncontrolled, but once it has disappeared it seems to be in a totally bugged state (telemetry of the unit goes all over the place) which can induce the freeze.

Yesterday I cooked up a mission in the ME (so not a Retribution generated mission) which seems to consistently trigger the freeze, given you run it on a dedicated server and connect as client of course:bird-flipper.miz

The mission will run for roughly 20mins before freezing, i.e. the point where the first MiG-29S from Min-Vody gets shot down by the F-15C CAP flight, which triggers the freeze within seconds of the kill. This was confirmed to also cause a freeze on @Biggus' end, and I believe @Drexyl also confirmed this, whom I'd like to thank for their extensive testing because there's no telling how much extra time I would've spent on this before being able to put my finger on the issue.

Obviously I took it a couple of steps further, and so I started going deeper down the rabbit hole w.r.t. uncontrolled aircraft on the ground, to see whether they also cause issues, and interestingly enough they do cause issues, but not a freeze. The next  mission is basically a copy of the bird-flipper, but had additional aircraft parked at Sochi which remain uncontrolled: bird-flipper+uncontrolled.miz

On my end this resulted into a graphical bug as soon as the first bomb of the B-1 hits the first Viper, which should've turned invisible by the time the B-1's GBU hits the ground. My screen basically turns black for a moment, then I get a picture again but only on the sides of my screen. Gradually the graphical bug fades out and things go back to normal, despite having "interacted" with an aircraft that got into this bugged state, which sort of suggests the freeze will only occur with bugged aircraft that were activated after getting into this bugged state, although at this point it's still an educated guess.

Thus, next up I thought I'd put this theory to the test, which is basically another copy of the mission, but instead of having a bunch of Vipers parked at Sochi I decided to go with one & drop the second bomb on "Aerial-1-4", which is a Su-24M that also seemed to bug out, yet at some point becomes visible again. Strangely enough, bombing the Su-24M didn't induce a crash, but then when looking closer it also seems like the Su-24M never loses telemetry, which may explain why it's not causing a freeze: bird-flipper+uncontrolled2-(bomb-on-ground).miz

That said, there's definitely another test I could run, because knowing that the MiG-29S is causing a freeze, I might want to try to bomb that instead and see if it still doesn't cause a freeze. Finally, as proof of the pudding, the same mission but without uncontrolled aircraft awaiting startup will work just fine: bird-flipper-fix.miz

PS: here a screenshot of an aircraft that went invisible, but take note of the telemetry:

Currently my guess is that that is the root cause of the freeze, i.e. once such a unit interacts with other units (like getting shot down) it will induce the freeze within seconds. Also noting that the freeze does not occur on the server's side (the server remains running just fine) but only on the client's side, which never disconnects. In fact, yesterday I noticed something interesting in one of my tests during such a freeze, i.e. if you wait long enough, you might actually see the frame change once or twice, so it seems like some very heavy processing is triggered on the client's side which is somehow the result of this "bad telemetry".

Last but not least, here's a small clip of an aircraft that's about to bug out:

Hopefully this'll be enough data to track down the root cause of the issue 

Edited December 30, 2024 by Raffson

[festr]

I have reported similar issue (reproducible) https://discord.com/channels/542985647502393346/1316771017632383049  with detailed .miz and backtraces when it freezes. I have edited .miz -> mission.lua and set all uncontrolled = true   to  uncontrolled = false  and this caused mine test scenario to not freeze anymore. 

[Woody01]

I am glad I found this report as we have not been able to complete a single multiplayer mission for months now. We have had the flickering aircraft/loadouts for a few months and I have to ask is it possible that because I use 'uncontrolled aircraft'/ Start trigger extensively in our missions could this be the culprit?  I am honestly at the end of my resilience with running a large online group that meets several times a week to fly unique missions only to start out with 20~ guys to get typically 2~ pilots actually make it to target due to everyone crashing out in one way or another and then, every time a coconut, the server crashing.

Could it be down to this bug? If so, it's an easy work around but also incredibly disappointing.

[Biggus]

2 hours ago, Woody01 said:

I am glad I found this report as we have not been able to complete a single multiplayer mission for months now. We have had the flickering aircraft/loadouts for a few months and I have to ask is it possible that because I use 'uncontrolled aircraft'/ Start trigger extensively in our missions could this be the culprit?  I am honestly at the end of my resilience with running a large online group that meets several times a week to fly unique missions only to start out with 20~ guys to get typically 2~ pilots actually make it to target due to everyone crashing out in one way or another and then, every time a coconut, the server crashing.

Could it be down to this bug? If so, it's an easy work around but also incredibly disappointing.

Try to plan some missions without uncontrolled AI and see how you go.  I've gone from all users having crashes within an hour every night on my dedicated server to maybe an unrelated crash every two or three weeks.

[Woody01]

Yea very interesting. As I say if you know what it is it is an easy work around but if you don't, well, we have nearly disbanded our 20-year group over this.

[Raffson]

I believe this thread can be closed as this was fixed about a month ago.

[festr]

for me its fixed. 

[Flappie]

@Raffson@festr Thank you gents, it's been fixed indeed.