Simobjects are not displayed on one graphics card

[michalbon]

Hello All,

I have an ATC simulator built on 6 TVs. The whole thing runs on one computer with two RTX 2080 graphics cards.
In the simulation we generate smoke and fire effects which are superimposed on the aircraft model. The effect is visible on TVs connected to one graphics card, but is not visible on TVs connected to the other one.
There is also such an effect that the "burning plane" when it moves from one monitor to another (from one graphics card to another) suddenly stops burning - the smoke/fire model is no longer visible.

What could be the reason that simobject is not displayed on TVs connected to one graphics card, but is displayed on TVs connected to the other one?

Best regards
Michal Boniecki

[Beau Hollis]

Our particle effects simulation run on the GPU using compute shaders. When multiple GPUs are in use, we run one simulation on each GPU and submit updates to both each frame to keep them synchronized.

Can you provide more specifics about how these effects are generated/placed/managed?

Do you see similar issues with effects in our default content? (smoke stacks, engine smoke, boat wakes, etc)

Thanks

[michalbon]

Hi,

Thanks for your answer. I have done various tests today:
1. I tested how the Police car works. I have used for this Veh_police_Cruiser_Sm model. The flashing lights on the car only worked on the first graphics card. So it looks like the problem is also affecting the effects in Prepar.
2. The problem only occurs in view groups mode. When I extended one window to all 6 TVs the effects were displayed correctly.
3. I checked also visualization without view groups - on each TV separately I opened separate window - also effects on card 2 were not visible
4. When there is visualization only on TVs connected to graphics card number 2 and there is no visualization on graphics card number 1, effects are displayed correctly. It is enough if at least one additional window is on TVs from graphics card 1, then the effects disappear on graphics card 2

The effect (simobject) that we generate is in the form of an object with animation. The object is a cloud of smoke or smoke with fire. We enter this object into the simulation just like the AI planes. All objects entered this way work correctly except for the lights in the cars and the effects (fire, smoke). I have no way to check if the default effects work properly, but if the effects in the default cars don't work, I suspect they won't work either.

It looks like the problem is not really related to the graphics cards themselves or the card drivers. It's more like some sort of object generation bug that appears on a different graphics card than the one responsible for rendering.

For information, I am using Prepar3D v5 Professional Plus, currently in the Developer version.

I am kindly waiting for instructions on what else should I check.

Regards
Michał

[michalbon]

Beau,

I managed to test the operation of the default effects. The effect is as shown in the pictures. On the left televisions the effects are there, on the right televisions connected to the other graphics card they are not.









Regards
Michał

[Beau Hollis]

Thanks for all the detailed reports on this. We were able to track down the issue and it will be resolved in the next release.

[MistyBlue]

Sorry to bring this up after so long, but did this issue ever go away for you? It seems to either still exist, or not completed fixed because I seem to have a similar problem with version P3D Professional Plus 5.3.17.28160.

In my case, AI aircraft dynamic lighting effects disappear across displays on the same card. I am using with a View Group for 6 displays. Two separate PCs, though, with one card in each PC connected to 3 displays. On each PC the dynamic lighting effects only work on one of the 3 displays.

I don't know if Beau is still there, but if so, I'm wondering if there's any tweaks I can make to fix the problem or it's something deeper?

[JorgenSA]

Tony, you noted what Beau said: "Fixed in next release".

The only thing you can do is what the rest of us are doing: wait.

Jorgen

[MistyBlue]

Jorgen, the OP posted this a year and a half ago. It appears a very similar problem to mine that IS or WAS an issue that LM acknowledged back then and not related to drivers or hardware. It also appears not to have been fixed, or fixed completely in the "next release," which by the way, I believe was version 5.3.12.28072 released Dec 2021. This was after Beau's statement was made. I'm on 5.3.17.28160 (Jan '22) which is now two versions later. So I think it's fair to say I have "waited."

Since another person on my original post has indicated they have the same issue, I stand by my assessment that this is a Prepar3d problem. So I'd like to know if the OP's issue was actually really ever fixed. If not, I'd like to know what happened with the fix.

I know you're trying to help, I hear you and I appreciate it. I just don't agree that sitting around waiting and "hoping" it'll get fixed is the right answer.

[MistyBlue]

Ignoring the spam poster above, this reminded me about this post. Beau mentioned he discovered the cause of the problem and it will be addressed. Fingers crossed it finally solves the problem.

[Beau Hollis]

I looked back at the commit logs. The issue fixed in 2021 was tied to the use of multiple gpus. The other issue turned out to be related to using multiple views/displays on a multi-channel client and could be replicated even with a single GPU. The multichannel issue has now also been fixed, and that fix should be available in the next release (with the clock resetting to today). Thanks again for helping us track these issues down.

[MistyBlue]

Hi Beau, looks like the issue has been fixed on v6. Looks great! Thank you!

I know it's a stretch, but is s there any chance whatever the fix was can be easily applied to v5 as well? Like a simple DLL copy? I still get better performance out of v5 in a multi-channel configuration, plus more of my addons are natively supported on v5 so I'd like to stay on it for a while yet.

[MistyBlue]

Hi Beau, looks like the issue has been fixed on v6. Looks great! Thank you!

I know it's a stretch, but is s there any chance whatever the fix was can be easily applied to v5 as well? Like a simple DLL copy? I still get better performance out of v5 in a multi-channel configuration, plus more of my addons are natively supported on v5 so I'd like to stay on it for a while yet.

Never mind...forgot I asked the question in the following thread already, and you replied that it would be a candidate for a future update for v5 if there was one.

https://www.prepar3d.com/forum/viewtopi ... 89#p269689

Have a Happy New Year everyone!