AnkH

Dusk and Dawn performance problems...

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Posted (edited)

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 by AnkH

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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.

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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.

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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.

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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.

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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...

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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?

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

DAWN_DUSK_SMOOTHING=0

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35 minutes ago, Midnight Music said:

DAWN_DUSK_SMOOTHING=0

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

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Posted (edited)
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 by Farlis
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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...

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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?

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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?"

 

 

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

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LOL as much as you want. It should be obvious by reading what I adjusted for my graphics preset that I actually READ some stuff about what could be the culprit and that I am lost as most if not all possible solutions did not help in my case. I DID turn off cloud shadows and a lot of other shadows as mentioned in post 1, then I wonder why three possible answers simply provide links to the solution called "turn off cloud shadows" or even mentioning this directly. It is not my fault if people only read the title and then give an answer, sorry...

The shader story I did not mention, my bad. But as clarified in a later post, I wrote that I already disabled "cloud shadows depth" and it did not help.

Anyway, even if it sounded like, I am not mad and thankful for several hints here, I will certainly try them (again...).

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13 minutes ago, AnkH said:

LOL as much as you want. It should be obvious by reading what I adjusted for my graphics preset that I actually READ some stuff about what could be the culprit and that I am lost as most if not all possible solutions did not help in my case.

What's with the 'tude man?  It's all about helping people and sharing info.

The only thing obvious here is that you haven't reverted to stock shader files yet.

Just disabling shadows in-sim won't do it all, depending on shader settings.  

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Ok, I downloaded the newest PTA preset from Adam and unselected "cloud shadows depth" and "cloud shadows extended" size, rebuilt the shaders, checked again that cloud shadows were off and tried again. Now FPS are back to acceptable levels, still lower than in day time or full night time, but acceptable.

Sorry for my rather harsh attitude, but not reading what I wrote is something that drives me nuts in todays forums. I apologize for being unfriendly in some answers and thanks anyway for the help. It for sure pointed me in the right direction, thanks for this.

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So I didn't see where anyone explained why this is happening, so I thought I'd help with a little foundation.

P3D, like in FSX, uses a combination of day and night textures to visually create Dusk and Dawn textures.  So the performance drop you're seeing is because the sim is loading both day and night textures to present dawn and dusk to you.  Because this is what's causing that performance drop, there really isn't very little you can do about it.

 

Of course you can mitigate the performance impact by fine tuning your settings. I didn't see any system specs, but if you're running a slower computer or laptop then you may have to run during the day or night or at least set your time so that it's day or night when until you get above 18,000ft (below this flight level, a lot more graphics are loaded).

I hope this helps.

Oh, system specs?

 

 

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4 hours ago, AnkH said:

Ok, I downloaded the newest PTA preset from Adam and unselected "cloud shadows depth" and "cloud shadows extended" size, rebuilt the shaders, checked again that cloud shadows were off and tried again. Now FPS are back to acceptable levels, still lower than in day time or full night time, but acceptable.

Thanks for pointing out these two settings in PTA -- I remembered having this problem but I couldn't remember what I unselected.

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12 hours ago, DaveCT2003 said:

Oh, system specs?

Thanks for pointing this out, Dave (the above part I did not cite, not the system specs ;-)). My system specs are in the signature part of my posts...

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On 1/9/2019 at 1:54 PM, AnkH said:

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...

I have the EXACT same issue, same observations, same everything. Performance is GREAT at all times except dusk (and dawn), when FPS drops to often single (!) digits. Tried with and without Tomato Shade, with and without PTA, not much differece, in fact, performance during these times of the day is awful for some reason.

However, it wasn't always like this. At least, not completely. When I switched to P3D from FSX, the current version of the sim was 3.2, it was in April 2016. My PC back then was the same as it is now, but the graphics card was different, that time I was using a GTX 970 card. It's an Intel 6700K at 4.5 GHz, with 16GB RAM, 2 SSDs and a HDD. One SSD is solely for P3D, one is for the OS (Windows 10) and the HDD is for everything else. I do remember I had the same issues back then during dusk and dawn, but not during other times of the day. On the contrary, performance was (and is) great during broad daylight and / or night time, no matter the scenery, the weather, the settings or the aircraft complexity. I have been using more or less the same settings since I switched to P3D.

Now, something must have happened perhaps as a result of the introduction of later versions of the 64 bit V4 because after 4.1 or so, all of a sudden I no longer observed the massive FPS drop. To celebrate the new sim I also upgraded my card to a GTX1070 which I am still using. Initially I still had the FPS drop during dusk and dawn even with the 107, I was very sad and disappointed but suddenly, bang, I did not experience FPS related issues all the way until I abandoned P3D last June and returned a month ago to V4.4 which was very inspiring so I decided to restart my P3D journey. Installed everything from scratch, everything is up-to-date, I mean, everything. But for some weird reason, I couldn't enjoy the grand return because the old evil, the dusk/dawn FPS loss seems to have returned too. Be it the FSLabs A319/320, the QW787, the Leonardo Maddog, the PMDG 737, 747 or 777, all the same, FPS drops like crazy, often below 10 during sunset and sunrise. It last for about 15-30 minutes and as soon as the sun rises or sets completely, FPS returns to normal. In the VC of the PDG 748 I usually get 50-60 FPS during day and night in the crusing altitude and around 30-50 on the ground, depending on the scenery. Worst hit for me is FlyTampa's KBOS that reduces my FPS to around 25 in complex aircraft when lookin towards the terminal. But even that is still fine. But the dusk/dawn hit is not fine at all.

It's obviously not the shaders, not the aircraft and not my settings since the exact same shaders, aircraft and settings were used earlier without issues. I am guessing LM reintroduced something that affects certain systems only since not everyone has this issues, but many of us still does.

I am now considering upgrading my card once again, only a year and a half after buying the 1070, since it's terrible not to be able to enjoy a proper sunrise/sunset. A dusk departure from let's say London to New York across the Atlantic is a nightmare since it means chasing the setting sun, basically I am then stuck in the nightfall, resulting in an elongated low performance period. I am hoping a GTX1080ti will solve this issue but when I bought my 1070 I thought the 1070 will be enough...

Edited by kityatyi

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I also noticed such issues and traced to vegetation shadows.

Where the low sun of dusk/dawn was producing long complex shadows and of course there were hundreds of trees and thusly maxing out my GPU (1070Ti) to the point where it couldn't handle it any further (not to say there are not other reasons, just in my case this is what I found during monitoriing of the CPU and GPU sessions in my close to the ground GA style of flying).

So now I don't bother so much with vegetation shadows for dusk/dawn and have separate tuned config profiles to change on the fly.

I discovered that with vsync on and a monitor Hz rate of 30 I would get a very smooth 30 FPS and would also greatly reduce the GPU load (as compared to a monitor Hz rate of 60 which with vsync on would be a max of 60 FPS), meaning the GPU would only have to work half as hard for the same output and I could successfully ramp up the P3D details settings without overloading the GPU and killing off the frames.

So now I have a selection of tuned profiles that mean I can chose a profile for the type of flying I'm intending to do.

Do need a monitor capable of 30 Hz though, or alterantively a CPU/GPU that is capable of exceeding 60 fps in even the harshest of CPU/GPU driving.

I chose the monitor route as it was the least expensive option and best bang for the buck when it came to smoothness and great detail levels.

Cheers

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8 hours ago, kityatyi said:

I am now considering upgrading my card once again, only a year and a half after buying the 1070, since it's terrible not to be able to enjoy a proper sunrise/sunset. A dusk departure from let's say London to New York across the Atlantic is a nightmare since it means chasing the setting sun, basically I am then stuck in the nightfall, resulting in an elongated low performance period. I am hoping a GTX1080ti will solve this issue but when I bought my 1070 I thought the 1070 will be enough... 

Don't expect too much from a new VC.Even my system with RTX 2080Ti still struggles in NYC and London area.

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3 hours ago, Nemo said:

Don't expect too much from a new VC.Even my system with RTX 2080Ti still struggles in NYC and London area.

That is weird. I have no issues whatsoever i neither the London nor the NY area and my sliders are mostly set on the far right. True though, AA is set only at 8xMSAA, more would eat my frames like a hungry beast. But in general I do not experience any performance issues in any aircraft, any scenery, it's only the dusk and the dawn. Anyways, for the peace of mind the 1080ti will come soon but it seems there is something else I need to look into. I remember, when the fall 2017 Windows 10 update came, I started to experience screen tearing and I turned on Vsync and Triple Buffering. That was more or lesss when I started to forget about the dusk and dawn issues, maybe turning these options on did help somehow? I will give it a try and text during the next few days, turning Vsync and Triple Buffering back on once again. Let's see.

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