Hello,

 

I have been using DX10 Fixer for 6 months or more and love it. I hope some one here may be able to help me with a sever Frames Per Second drop I get when engine smoke or water spray enters the cockpit, my frames drop from 30FPS to 6 or 3FPS.

 

I have been searching through forums and found some mentions of " smoke particle effects" as being at fault but no sure what this means.

 

I am wondering if there is any DX10 Fixer setting that may help or is there some replacement smoke effects that will fix the issue. I do not think DX10 Fixer is at fault.

 

I have tried lowering the AA in DX10 Fixer from 8X to X4 and made the adjustments to Invidia Inspector and FSX CFG, the frame rates improve a little but still drops from 30 to 8FPS or lower.

 

I have a I5 2500k 4.7GHZ, GTX680 4GB, 8GB Ram, 3 x SSD's. WIN 7 64bit. I update the Nvidia drivers a couple of months ago and the issue ddi not get worse or improve.

 

Cheers,

Sebastian

What happens if you uninstall the fixer libraries is run w/o the fixer is this frame drop the same?

Hi Steve, yes I seem to get the same drop in FPS with the libraries off.

 

I also just tried DX9 and there was no FPS drop apart from some when I got some dark grey smoke from a sibwings addon aircraft which i purposely over heated the engine to test the smoke.

 

Seb

Steve could I try converting All Effects? would it help with smoke particle i have read about but do not understand. At the moment I run DX10 Fixer Lights/Effects set to "Effects Lights only".

If it occurs without libraries then it is unrelated to the dx10sf effect conversions so no settings there can make a difference. Are you using any effect addons? Dies the problem occur with the default Cessna?

Hi Steve, yes I get the same issue with the cessna and many of the default aircraft but its a lot more noticeable on the addon aircraft, I guess they throw up a lot more smoke and spray. I just did a test in the same scenarios, wet run way ops with strong winds to blow the water spray into the cockpit and engine fire mid air with the default 172 and the A2A 172. The A2A 172 was worse on the wet runway but in the engine fire they where almost the same. The engine fire drops the frame rate a lot more double what the white smoke does.

 

I was posting here as I thought some one in the community or you might have some tips. I never suspected DX10 Fixer as the cause but was hopping it might help.

 

Thank you for such a great addon Steve and any one else who worked with you on the DX10 Fixer.

 

I am suprised I have not found only a few post on the forums about fsx and smoke affects. I cannot be the only person who has experienced this issue. Even P3D V2 has issues with smoke from what I have read.

Are you using fsx dvd or steam?

FSX DVD is what I am using. I have never installed FSX Steam but I do own  a copy.

Can you look at the aircraft.cfg for the c172 and tell me the contents of effects section? Assuming water is set to fx_spray can you tell me the size and date of fx_spray.fx in the fsx effects directory. if any of this doesn't make sense ask and I will give more detailed instructions. Do you have a processor affinity mask set in fsx.cfg and if so what is it?

Hi Steve,

 

I found a P3D forum that may help, it is talking about the exact same issue of the affect on FPS of spray, smoke and dark engine fire smoke. They even show some screen grabs in the forum that are exactly what I experience. Also an important point is that the FPS drops more in relation to how much of the screen is covered by the smoke or spray. So its worst when it fills the entire screen. http://www.prepar3d.com/forum-5/topic/extremely-low-fps-with-smoke/page/2/

 

But to answer your request, the Cessna 172 CFG file states:

 

[EFFECTS]
wake=fx_wake
water=fx_spray
dirt=fx_tchdrt
concrete=fx_sparks
touchdown=fx_tchdwn_s, 1

 

Spray effect;

fx_spray.fx created 12/05/2006 size 5kb

 

 

I found this two posts most interesting, It would seem that only turning off effects gets rid of the problem but we loose the effects, what do you think.

 

1) Interesting. Could you all let us know which aircraft and effects are slowing things down?

The GPU particle system is capable of rendering several times as many particles as the old system at much higher FPS. That said, it scales better when the effects aren’t filling the screen. For example we created a forest fire stress test where we kept growing a grid of forest fire effects over time. In 1.x the total number of particles was set pretty low so doing this would lead to a scattered broken up scene or to some effects not emitting particles at all. In v2, they could all emit and the system stayed at a decent frame-rate. Granted we did those tests before we had the tessellation and shadows working, so the overall stress on the GPU is likely higher. I think the main issue is that the pixel shader is actually fairly expensive so when you have particles up close filling the screen you get lots of overdraw. If you’re running 1080p that’s close to 2 million pixels on screen so if you have hundreds of nearly full screen particles, it could be a problem. Perhaps the effects causing this issue have a high emission rate and large scale. This might not have been a problem in the v1/FSX where the system would scale all the emitters back in high load situations. We clamp the total particle count too (which is what that slider controls) but its much higher than it was before.

We do plan to go back and do more optimization int he particle shaders once we get the major bugs out of the way. That should help speed things up when flying through effects.

Beau Hollis
Prepar3D Rendering System Lead

 

2) For reference, I have/had this issue with FSX.

In P3DV2.1, if I turn AA completely OFF the fps drop is very minor. Obviously don’t want to fly without AA, but I was wondering if perhaps the particle system can be set to prevent/disable AA?

I know when using Steve P’s, DX10 Controller/fixer product with FSX DX10, there was an option to disable MSAA on clouds (handled thru shaders) which makes sense, clouds are high alpha and typically no sharp edges so no need for AA. Same would apply to smoke and particle effects.

Just a thought for the LM team.

Cheers, Rob.

Hi do you have a high level for super sampling set?

I have 8x supersampling, I had tried 4x supersampling. I have not tried NO AA setting because even if it works the flightsim would not look good at all. I will have to try to avoid smoke and spray coming in the cockpit. I was trying to find a fix but I doubt there is one.

8x is a lot, I use 8xcsaa and 4x sssgaa. From what you describe the overdraw cost is more likely to be super sampling rather than the base aa.

I will try X4SGSSAA(again), 2XSGSSAA and None AA and see what happens and report back. Thanks for your time with this Steve as its not really a DX10 issue because it happens in DX9.

 

Steve could it be simply that the smoke affect in FSX is very old and not written for modern GPU's.

Hi Steve,

 

I tried no AA and there was no FPS drop, tried 2X and 2XSGSSAA there was a slight but acceptable FPS drop from 30 to 25ish. At 8xCSAA and 4xSGAA FPS drops to 3 or 2 and the my screen turns into triangles, the GPU or CPU just cant cope.

 

I used a extreme test, flying a default mooney bravo and forrest fires from Orbx KWYS scenery. the fires produce a large amount of smoke. I am going to try 4x and 4xSGAA.