Seated passengers cause patterned stutters with the beacon light on

[946620]

I’m running into an odd issue with GSX and the Fenix A320 in MSFS 2024 regarding seated passengers.

What happens:

If I enable seated passengers in GSX, it immediately triggers an update request in the Fenix Installer.

If I install the Fenix update, GSX services work normally, but seated passengers no longer appear in the cabin.

If I do not install the Fenix update and keep seated passengers enabled, the passengers do appear, but the sim suffers from very heavy stutters, making it almost unusable.

So basically:

Update installed → no seated passengers

Update not installed → seated passengers work, but severe stuttering

Question:
Is this a known compatibility issue between GSX and the current Fenix A320 version in MSFS 2024?
Is there a recommended workaround, or should seated passengers be disabled entirely for now?

Any insight from FSDT or Fenix devs (or anyone who has tested this) would be appreciated.

*EDIT* TESTED WITH BOTH INIBUILDS A350 AND FENIX A320.

[Jonald]

Hey,
Also having this issue as well - to be honest, I didn't know why each time I ran the Fenix installer, I had an update pending now I know why.

I see passengers board  but they dissapear when they get to their seats. Opening / closing the door doesn't make them appear either so I think it's a conflict of some sort.
Following this post.

[946620]

It's a strange issue.

I seeked support from Fenix who informed me that this is a known issue with GSX and that they are unable to do anything to fix the issue.

The stuttering only starts once boarding has been completed. Before that point, there are passengers seated with no stutters.

[946620]

Kindly bumping this topic.

[946620]

So it appears there's another forum topic relating to this issue:

https://www.fsdreamteam.com/forum/index.php/topic,34047.15.html?

[virtuali]

You are discussing two completely different issues:

- The Fenix installer reporting a small update if you enabled Seated Passengers. That's of course a Fenix installer issue, that is considering as an "update" any smallest modification to any file in the airplane, which of course is the only way to enable seated passengers. So, just ignore the update, because if you do, the "update" will restore the airplane model files to their original status, without seated passengers.

- Stuttering with Seated passengers enabled. Seated passengers are surely not free, especially if you have the cockpit door opened. However, I don't see much impact with the cockpit door opened.

However, while in versions until SU3, the impact of seated passengers not visible (cockpit door closed) was ZERO, in SU3 what was clearly a bug has been introduced that resulted in a very bad fps impact. This improved quite a bit with SU4, however it seem the impact of invisible passengers is still not *exactly* zero as it was until up to SU2 (and still is in MSFS 2020). 

You must understand that, Seated Passengers are NOT controlled by GSX. There's no code "running" them: they are part of the airplane and, other than setting the variables to turn them on/off (because their seat is empty/occupied or the cockpit door is closed), GSX has no control over them, and it's up to the sim to do its job of properly optimize objects that are not visible. Other than making all passengers extremely well optimized and with multiple LOD levels (and we surely do), there's not much we can do to control this.

Note that, as with EVERYTHING in the sim, there's NO single thing the "cause" performance problems. Your final performance is always a SUM of *everything* and, the performance effect of some function is NOT linear.  If your settings are close to the maximum your hardware can handle, you might be fine, but then see a dramatic drop if you just add something else that would cross the threshold between being fine or not.

So, in the end, it's just a matter of what it's more important to you, and that's why Seated Passengers not only are optional, their are not even enabled by default, on any airplane.

[946620]

Many thanks for your reply, Umberto.

I have performed some extensive testing this morning and when the Seated Passengers board the Fenix A320, performance is awesome (as it always is with GSX). As soon as the beacon light is switched on, the sim stutters. As soon as the beacon light is switched off, the stutters disappear. This is surely an issue linked to the GSX integration with the Fenix as without the Seated Passengers enabled, and with GSX running, there are absolutely zero stutters when the beacon light it switched on.

[virtuali]

As soon as the beacon light is switched on, the sim stutters. As soon as the beacon light is switched off, the stutters disappear.

That's even another separate issue. By the time you turn on the Beacon light, passengers has been already sitting for a while, so they all already transitioned from being partially under GSX control (during Boarding, when the Walking passengers are controlled by GSX and the Seated just attached to the airplane), to be completely under the simulator control, and nothing really happens to seated passengers when the Beacon light is turned off, other than GSX creating the pushback crew, which is at most 3 people, which is nothing compared to the 100+ walking passengers we previously handled.

One thing to try is starting GSX Departure with the menu, instead of the Beacon light, and see if there's any difference.

[946620]

Many thanks, Umberto - I will try that and will report back to you 👍

[946620]

Hi Umberto

I have performed some more testing this morning and if I manually request pushback through the menu, rather than it being automatically triggered by the beacon light, as soon as the beacon light is switched on, the sim encounters moderate and regular stuttering. This is an issue that is definitely being caused by the beacon light. I am afraid that I'm almost certain this is a GSX issue as the Fenix beacon light does not cause these stutters when Seated Passengers are disabled.

[virtuali]

This is an issue that is definitely being caused by the beacon light. I am afraid that I'm almost certain this is a GSX issue as the Fenix beacon light does not cause these stutters when Seated Passengers are disabled.

That definitely proves it's NOT a GSX issue, instead because, if I understand your report, you have no issues with Pushback itself (when called from the menu), it's the beacon light *itself* that causes the problem.

Which reinforce my previous theory that, it's JUST a matter of the beacon light being a dynamic light, and possibly affect performances just because there's just extra geometry (Seated Passengers) and the light is close enough to the passengers to have this effect seen.

Small clarifications how dynamic lights work in ANY graphic engine:

There are TWO ways to make dynamic lights, forward rendering or deferred rendering.

Most of the modern engines use deferred rendering, but I'm not 100% sure which one is used in MSFS and if it's always used in any situation or with every light type but, no matter the method used, BOTH are affected by the geometry the lights projects onto, it's just that forward rendering is affected more, because its cost is geometry * number of lights, while with deferred rendering the number of lights is not multiplied by the geometry (because geometry is calculated only once, not once for every light), but that doesn't mean geometry doesn't matter, because it still does, just less than with forward rendering.

Basically, regardless the method used, dynamic lights are affected in some way by how many polygons they are projecting over, and that includes everything in the scene which is in the range of the light so, airplane, cabin, airport, other nearby vehicles AND seated passengers, all counts.

[946620]

Many thanks for the explanation. In terms of this issue being fixed, do I need to forward this topic to Fenix or is this something you can discuss with them?

[virtuali]

IF the problem is just geometry complexity affecting the dynamic light, I'm not sure anybody can fix it.

Maybe reducing the light radius might improve it, but that's just a guess, but I guess (hope/assume) the current radius is correct for what the beacon light is supposed to do, and I doubt Fenix would want to reduce the complexity of the airplane cabin just to compensate the increased geometry complexity due to having attached many passengers. You can of course choose not to use them.

There's an easy way to see if my theory of this being simply a geometry complexity issue, and is to create a flight plan with maybe 1 passenger, and see if turning the beacon light on has the same effect or not.

[946620]

Hi Umberto

All of my testing was done with just 1 seated passenger. The stuttering is still present with just 1 passenger and with a full load of passengers, the stuttering is the same level.

[946620]

Hi Umberto

Should I raise another support ticket with Fenix or is this something you can fix?