investigating JHCMS mark point drifting

[CoconutCockpit]

Preface:

• I have a particular .miz file where this problem happens.
• If a make a new mission on the same map (NTTR), the problem doesn't occur.

Problem:

• Mark point made through JHMCS starts drifting after pressing TMS up once to ground stabilize. 
• Press TMS up again to save the mark point and it continues drifting.
• Happens both in single player as in multiplayer
• Happens both on normal server as well as dedicated server

Question:

• Why is this one .miz so special that it's causing this issue?

Attached are both track files: one with the problem and another one where the problem doesn't happen. I know I can remake my mission in a new .miz file, but it was quite big and had a lot of things on there already. So if there's a way to fix this without having to remake it from scratch, that would be great. 

jhcms_mark_point_drifting.trk jhcms_mark_point_ok.trk

Edited March 29, 2023 by applepiefrost

[Lord Vader]

Hi, @applepiefrost

The mark point you are creating isn't drifting. It's, in fact, floating mid air. Although the altitude registered in the mark point is correct, the actual visual representation in the HUD and HMD is not. Even steerpoints created on ground level seem to be floating. Depending on terrains, it's about 100ft above. 

Without context, It's hard to say what happened to provoke this offset. It could be a previous altimeter setting, set in an older version of DCS or the module itself, for example. 

How long has this mission been created? Did you change any altitude or altimeter parameters for it?

[CoconutCockpit]

Ah, you're right. The QNH for the mission where the mark points get created in the air was set to 30.08. I completely forgot and never changed it during my start up of the jet. 

I don't remember when exactly I saved the first version of this mission, but I'm pretty sure it was before the multi threading client was added. I then saved over it dozens of times using the MT client. I did try in both the normal and the MT client though and got the same results. 

Some things to note though:

• `mission["weather"]["qnh"]` in the `mission` file was set to 764 (torr), which converts to 30.08 inHg. So just like I set it in the Mission Editor
• I air start in the .trk file, and you can see that the value in the jet reads 29.92. Looks like it's not set to the same value that is set in the Mission Editor
• I attached another .trk file where I start hot from the ground
  • The value in the jet reads 30.08, so that seems to be correct
  • When I make a mark point, it still floats above the surface it seems

I don't know, maybe there's another problem with the QNH settings? It seems that when I make a mission and just leave it at 29.92, everything works fine. I don't have the time to further investigate this now though, but might be worth looking over from your side. 

jhcms_mark_point_in_air.miz jhcms_mark_point_in_air_hot_start_ground_qnh_ok.trk

[Lord Vader]

The issue here is that if I create a mission from scratch, I can't replicate this. Only on your mission/track do I get this. Which is weird.

I will continue to investigate, but my advice is that you rebuild this mission if you can. 

[CoconutCockpit]

I understand, that's fine. I managed to copy over everything I needed from the old `mission` into a new one so it didn't end up being much work as all. Thanks for pointing out where it went wrong though!

[CoconutCockpit]

On 3/29/2023 at 6:21 PM, applepiefrost said:

I air start in the .trk file, and you can see that the value in the jet reads 29.92. Looks like it's not set to the same value that is set in the Mission Editor

Just came back to DCS after a long time and noticed this is still an issue. If you air start the jet, the QNH in the cockpit says 29.92 even if the QNH in the mission editor is set to something else. I would expect it to copy over the settings from the .miz file.