Hi all,

As with 4.4 the dynamic lighting was improved, I started to fly again into night time or night time only. However, I still need a special graphics profile for night time flying with reduced settings, but that's fine. To properly set up my sim for night time flying with DL, I used again "my" test scenario, which is LSZH from AS, as this scenery is still pretty hard on FPS. I managed to find a setup with reduced shadow options that provides me roughly the same performance as my pretty high daytime settings (30FPS lock). Means: I now get 25-30FPS in most scenarios while flying in the night, perfect. What did I adjust: 4xMSAA instead of 4xSSAA, no cloud shadows, no building shadows, no terrain shadows, almost all reflections reduced, shadow draw distance reduced.

HOWEVER: flying in dusk or dawn time still brings my FPS down to around 10. And I have no clue why. No matter what graphics profile I use, the FPS in dawn or dusk is just ridiculous. Last flight I did in dusk was from JustSim EBBR to AS EDDK, never got more than 15FPS. First, I thought that the DL in EBBR was bugged, but as it remained that low outside EBBR and while approaching EDDK, I knew something else is bad. To confirm, I simply put another time, fully night time, and bam, FPS were back to 25-30FPS in both EBBR and EDDK.

What can it be? Why is the performance so bad in dusk and dawn? Which setting could be the culprit? Thanks for any hint,

Edited January 9, 20197 yr by AnkH

8 minutes ago, AnkH said:

What can it be? Why is the performance so bad in dusk and dawn? Which setting could be the culprit? Thanks for any hint,

Are you using any shaders add-on? all I can think of is the amount of colour changes happening during Dusk and Dawn can have an impact on your system, one of my current flying PC is less powerful than yours and I don't see this issue but I am only using P3D Default shaders.

Regards,
S.

17 minutes ago, AnkH said:

What can it be? Why is the performance so bad in dusk and dawn? Which setting could be the culprit? Thanks for any hint,

AFAIK the rendering engine of P3D is working during dawn or dust much more, multiple renderings have to be done in a short timeframe. The fading between dark and light is heavy work.

Yes, I use PTA shaders and I already disabled one of the cloud shaders ("cloud shadows depth"). Will try once with the default shaders or all cloud shader modifications off, good hint, thanks.

If your using aircraft such as PMDG try reducing the amount of lights you have switched on in the aircraft. I leave off Taxi light and RWY Turn Off Lights when on the RWY and only use half the landing lights, then when Taxing just have the Taxi light on. See if that helps. Having all the lights switched on kills my frames and I get terrible stutters.

As mentioned, I do not have ANY issues when flying in full night time, no matter how many lights on my plane are on or off. It is really ONLY during dusk and dawn, also independent of aircraft lights on or off.

One info that was missing in the initial post: the FPS drop is depending on the view direction. Means: looking away from the sun, my FPS are comparable to what I get in night time or day time. Looking in the direction of the sun +/- 45-60°, the FPS drop down to 10FPS or below.

Will test with the shaders this evening, hopefully it is just that. Then I have to think about solving this for me... Disabling PTA is no option, but if only some of the PTA presets can be disabled and the problem is solved, I could live with it...

18 minutes ago, AnkH said:

Looking in the direction of the sun +/- 45-60°, the FPS drop down to 10FPS or below.

Longer shadows because of the low sun?

Been doing this in the Graphics section of the cfg ever since FS9.

DAWN_DUSK_SMOOTHING=0

35 minutes ago, Midnight Music said:

DAWN_DUSK_SMOOTHING=0

This helps? What is it about anyway? What is smoothed when active?

You might try looking through this thread (and remembering in the future that the search engine is your friend):  https://www.avsim.com/forums/topic/517818-p3d-v4-dawn-dusk-night-performance/

Also this one: https://www.prepar3d.com/forum/viewtopic.php?f=6312&t=11966&p=41073&hilit=smaller+shadow+cascades#p41073

Regards

6 hours ago, AnkH said:

flying in dusk or dawn time still brings my FPS down to around 10. And I have no clue why.

The answer is the cloud shadows. Turn them off. Completely. And you will see the difference.

You can already tell that it is related to them by the fact, that the frames increase when you turn the camera away from the sun.

Edited January 9, 20197 yr by Farlis

Did you read my starting post? What did I wrote? That I use a specific graphics profile where I turned off cloud shadows, along with other greatly reduced settings. Yet the FPS drop remains...

49 minutes ago, w6kd said:

You might try looking through this thread (and remembering in the future that the search engine is your friend):  https://www.avsim.com/forums/topic/517818-p3d-v4-dawn-dusk-night-performance/

Also this one: https://www.prepar3d.com/forum/viewtopic.php?f=6312&t=11966&p=41073&hilit=smaller+shadow+cascades#p41073

Regards

Nice try. But of Course I searched for those threads and read them and no, in neither of those threads a solution is given. The first one is ended with a comment about cloud shadows which I turned already off, the other one is about v2.2 of P3D, seriously?

47 minutes ago, AnkH said:

Nice try. But of Course I searched for those threads and read them and no, in neither of those threads a solution is given. The first one is ended with a comment about cloud shadows which I turned already off, the other one is about v2.2 of P3D, seriously?

Of course the origins of P3D v4 go all the way back to FSX and even earlier...so understanding the issue as it has evolved is relevant.

Your post, asking what was going on during dusk/dawn, did not at all suggest you were aware of the material in those two threads...if you read through them it's pretty clear that during dusk/dawn double-rendering is happening, several (not just one) PTA shaders may need to be disabled, and Beau Hollis explained how shadow cascades cause issues when the sun is low on the horizon.  So, keying on the apparent lack of that basic information, I pointed you to the forum threads that discuss that.  If you had read that material, why then ask "Why is the performance so bad in dusk and dawn?"

 

 

Lol, asking for info and help then turning around and expressing indignation at those trying to help. “Seriously?”