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simmerhead

P3Dv4.1. Road Traffic Benchmark

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Road traffic is a known fps killer, but how much impact has it exactly? I tested it out with my setup - a vanilla install of Prepar3D v4.1. with medium high graphics settings. I used the avatar and placed him somewhere in downtown Tokyo. Weather and other AI traffic was turned off to isolate the fps impact from the cars as much as possible.

Of course, Tokyo has extreme levels of road traffic, but nonetheless you get an idea of just how much of an impact this setting alone can have on the sim. The biggest surprise for me was how much impact just 5% road traffic had. At 50% road traffic this scenario lost about 50% of its fps, and the sweet spot for me seems to be 10%. 

road-traffic-benchmark.jpg

2018-1-6_0-17-10-538.jpg

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Many thanks for your analyses

 

One question: do you have enabled shadows? (in the meaning that road traffic generates shadows?)

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1 hour ago, simmerhead said:

as can be seen in the screenshot

 

was not 100% sure when looking at the screenshot...

thanks for answering

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Thanks for this. Its why I have my road traffic at no more than 10%. I just want to see some cars going past regularly and that seems to be enough. Packed roads does not add to the immersion for me.

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So going from 5% to 10% impacted FPS by 2 only? Interesting. I guess I should go back to 10 from 5 then. Wonder how ships and leisure boats would affect FPS in the same scenario. 

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I think having shadows on the cars might have caused a lot of the FPS hit, how do the figures look at higher densities with AI car shadows disabled?

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Hi again. I loaded the test scenario and did a few comparisons (I did a slight change in my settings, so the fps baseline is a tad bit different from the table above). 

Anyway, here are the numbers (I load up the scenario and let things settle for a 2-3 minutes before reading the average fps):

50% road traffic, with Simobjects cast shadows enabled:          28,1 fps
50% road traffic, with Simobjects cast shadows off:                   28,3 fps (No major hit. I run shadow settings @ medium + medium)
50% road traffic + 100% ship traffic:                                           27,9 fps
50% road traffic + 100% ship traffic + 100% small boat traffic:  27,4 fps

Remember, these settings are relative to other settings and the location you're flying. But for airliner flying, which generally happens between larger cities, I find the numbers useful. Ship traffic probably has more impact in other places, especially around Seattle where there is a lot of ferries as well. The small boats are spawned on the fly as you fly over them, and I assum their impact is quite limited overall as well, although it will add additional workload to the CPU. 

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Great info! Thanks very much for the analysis...

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Thanks for testing that out. I guess it’s best to keep all 3 at 10% be done with it. 

For ships and boats 10% seems to be more realistic anyway or else it spawns a whole bunch of them in one small area instead of spread out in the ocean lol. 

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Thank you for taking all that time to test and report. I will keep mine at 0% 

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I prefer "Ships and Ferries" to be @ 100% - I like having the larger boats around - unless I'm using Henrik Nielsen's excellent Global Ship traffic package.

I keep "Small boats" @ 10-20% during summer, and forget about them during winter. 

 

Ships and ferries don't spawn like the small boats do. They act very much like aircraft traffic with ships following routes coded into a bgl file stored in the Scenery/World/Scenery folder. 

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2 hours ago, simmerhead said:

I prefer "Ships and Ferries" to be @ 100% - I like having the larger boats around - unless I'm using Henrik Nielsen's excellent Global Ship traffic package.

I keep "Small boats" @ 10-20% during summer, and forget about them during winter. 

 

Ships and ferries don't spawn like the small boats do. They act very much like aircraft traffic with ships following routes coded into a bgl file stored in the Scenery/World/Scenery folder. 

Doesn't that mean they use more overhead like AI Traffic? I don't mind keeping them high if they don't eat into performance.

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1 minute ago, TheBoom said:

Doesn't that mean they use more overhead like AI Traffic? I don't mind keep them high if they don't eat into performance.

The default ship traffic is quite sparse, so I don't think you will notice much performance degradation. 

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2 minutes ago, simmerhead said:

The default ship traffic is quite sparse, so I don't think you will notice much performance degradation. 

How about the freeware ship pack from the Avsim Library? I'm guessing it shouldn't change much?

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The file that controls sim performance vs road traffic is PopulationDensity.BGL found in:

<drive>:\Program Files\Lockheed Martin\Prepar3D v4\Scenery\BASE\Scenery

Microsoft made the same mistake with road traffic that they did with AI traffic in that the slider just controls the percent of the maximum value found in the bgl file for that geographic location. Thus, extremely densely populated cities such as London, NYC and Tokyo have incredible numbers of vehicles on their roads. Of course, in real life these cities have comprehensive mass transit systems and even though there are a lot of cars on the roads, the proportionality to population density is probably an anachronistic relationship. In any case, there should have been a limit to the maximum vehicle density per lane mile. Unfortunately, Microsoft never released the Living World SDK, so what controls road traffic is a static compiled XML file (LWConfig.spb). Users can decompile the SPB version to XML and edit such parameters as vehicle models used and vehicle speeds.

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And believe the small boat traffic is controlled the same way, being more numerous close to high population areas. It sounds like a logical system, but  it kills performance where you most need it of course...

Lets hope LM can create a fix. There really should be a limiter in terms of exact numbers instead of % for all traffic parameters. 

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2 hours ago, TheBoom said:

How about the freeware ship pack from the Avsim Library? I'm guessing it shouldn't change much?

Regarding that, (Global AI Shipping) I believe it is recommended to have the ship traffic under 10%. At least in FSX:SE FWIW..

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1 hour ago, HighBypass said:

Regarding that, (Global AI Shipping) I believe it is recommended to have the ship traffic under 10%. At least in FSX:SE FWIW..

Sounds strange. It's not my experience that it is fps hungry at all.

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Speaking of car traffic, has anyone tried the old method of editing each vehicles speed in their config file to slow down the vehicle traffic? This method has always worked for me but seems like in 4.1  they wont slow down regardless of changing the max speed. 

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The only way of altering freeway traffic speed is to convert the file LWConfig.spb to xml, rename the spb file to LWConfig.spb.old and edit each region's entry:

<FreewayTraffic TrafficSpeed="xx">

If vehicles had different freeway speeds they would crash into each other, so editing the vehicle's cfg file will not work for freeway traffic.

 

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2 hours ago, jabloomf1230 said:

The only way of altering freeway traffic speed is to convert the file LWConfig.spb to xml, rename the spb file to LWConfig.spb.old and edit each region's entry:

<FreewayTraffic TrafficSpeed="xx">

If vehicles had different freeway speeds they would crash into each other, so editing the vehicle's cfg file will not work for freeway traffic.

 

Thank you!

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13 hours ago, simmerhead said:

Sounds strange. It's not my experience that it is fps hungry at all.

You're right, but the 10% is limiting the default boats, not the Global AI shipping.

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