The sensation of speed

It's my first post here as I only got into DCS a few weeeks ago so first of all hello everybody.

I've been enjoying DCS a lot but there's something I noticed rather quickly. Especially when flying low, the sensation of speed is just not there.

The most obvious thing is the size of trees. This is definitely a major factor and I found an easy way to check this. I was flying low at about 600 km/h over trees and watching the fps counter. Then I flew above a road with a power line next to it. Despite the fps staying quite consistent, the perception of speed was noticeably different. The reason is that our brain figures out, based on the tree size, that we must be moving slower than we really are because trees that our brain is well used to are just not that big. Get away from the trees and look at the power lines and suddenly you feel you're going faster.

The second factor that I discovered plays a huge part is the monitor refresh rate. Most standard monitors it at 60 hz, which means you'll never see more than 60 fps displayed in-game, even if your GPU is a monster that runs the game at 150 fps. I learned you can "overclock" your monitor with the Nvidia control panel (no idea about AMD). If you're lucky, you might get a refresh rate 15-20 hz on the same monitor which will allow you to see these 15 or 20 more frames when flying. And God does it make a difference. Suddenly everything became smoother, faster and more real. I managed to reach 75 hz on my 60 hz Samsung monitor which I am not really satisfied with in terms of image quality, but at least it reached 75 hz which is already pretty good AFAIK. The catch is though that you need a PC powerful enough to run DCS consistently at 75 fps or whatever your maximum refresh rate now is if you want to take advantage of this.

I now regret not buying a higher refresh rate monitor. Though on the other hand my GTX 1060 wouldn't allow me to benefit from 120 hz or something like that anyway. It also makes VR more appealing to me now as even the Rift has a 90 hz refresh rate. That would also explain why some people flying in VR say their sensation of speed is OK.

Please share your experience with this issue. Who knows, other people might think there's no problem at all! I'd also be interested to know what refresh rate you guys were able to reach on your 60 Hz monitors if you are willing to try the method I mentioned. I'm wondering if the extra 15 Hz I got is good or average at best.

As to the trees, if there a mod out there or an easy way to reduce their size ? Also, do trees on the DLC maps have the same size or are they different ? It might be Caucasus only thoughI remember watching a video on Normandy map and they seemed too tall.

Could someone from ED comment on the possibility to include an option for normal/reduced trees in the settings ? It seems to me they need to be around 40% shorter and also narrower.

The perception of speed is very much tied to setup of FoV, lack of blur and the nature how humans perceive it from looking at 2D screen. Try a high speed flight at low altitude in some bigger city. Vegas or Dubai are good for this. The sheer amount of buildings there will give you better feel for your speed. But if you want to experience it in better way, try a VR set, the sensation of movement there is at completely different level.

Welcome to DCS.

I am one of them people thinking there is no problem with speed as sensation at all. Try dropping a bomb on a Land Rover from 500 feet at 500 KIAS, speed is there I would say.

Welcome to DCS.

 

I am one of them people thinking there is no problem with speed as sensation at all. Try dropping a bomb on a Land Rover from 500 feet at 500 KIAS, speed is there I would say.

Yes, the feeling changes dramatically when you are trying to do some "work" along with the flying. :D

Just move your fov / zoom back to how we would see it in real life and report back. Use num pad / and *.

Dcs concaves the view to widen the fov; so you see more on screen etc.

The perception of speed is very much tied to setup of FoV, lack of blur and the nature how humans perceive it from looking at 2D screen. Try a high speed flight at low altitude in some bigger city. Vegas or Dubai are good for this. The sheer amount of buildings there will give you better feel for your speed. But if you want to experience it in better way, try a VR set, the sensation of movement there is at completely different level.

It's the same think when you are inboard of a big plane ! You dont feel like you are travelling at 800 km/h !

Personnaly, the feel of speed and inverted come when I switch to VR ! :pilotfly:

 

Could someone from ED comment on the possibility to include an option for normal/reduced trees in the settings ? It seems to me they need to be around 40% shorter and also narrower.

...in the graphics settings for the quantity or you can develop your own flight simulator... Im pretty sure the trees in DCS are on scale !

Try it in VR at low level, its pretty good.

As to FOV, it's so obvious I forgot to mention it.:doh: Of course it helps a lot to fly zoomed out / with a wider FOV, but this comes at a cost of not seeing well enough in the distance. Perhaps a larger monitor with a higher resolution would be helpful here?

@chouclak Somehow the fact you're sure it's correct doesn't convince me it is.:smilewink: And when flying high, let's say 6000+ feet, it feels better than it does at low level. I assume it's due to the fact trees look natural from that altitude.

@Jumbik The problem is I don't have any of the payware maps yet so can't really compare, but I can totally imagine it's way better flying over a large city simply because the buildings appear to be the size of real-world buildings. Unlike the trees IMO. As I said, even in the Caucasus map flying over an area with no trees in the immediate vicinity or over a larger urban area improves the perception of speed for me.

It seems that in VR it's not an issue. I wonder if it has to do with the 90 Hz refresh rate. Do you guys actually get 90+ fps in VR, though? And how do you work out FOV in VR?

As to FOV, it's so obvious I forgot to mention it.:doh: Of course it helps a lot to fly zoomed out / with a wider FOV, but this comes at a cost of not seeing well enough in the distance. Perhaps a larger monitor with a higher resolution would be helpful here?

 

@chouclak Somehow the fact you're sure it's correct doesn't convince me it is.:smilewink: And when flying high, let's say 6000+ feet, it feels better than it does at low level. I assume it's due to the fact trees look natural from that altitude.

 

@Jumbik The problem is I don't have any of the payware maps yet so can't really compare, but I can totally imagine it's way better flying over a large city simply because the buildings appear to be the size of real-world buildings. Unlike the trees IMO. As I said, even in the Caucasus map flying over an area with no trees in the immediate vicinity or over a larger urban area improves the perception of speed for me.

 

It seems that in VR it's not an issue. I wonder if it has to do with the 90 Hz refresh rate. Do you guys actually get 90+ fps in VR, though? And how do you work out FOV in VR?

It's not really about the FPS, its more about natural FoV in VR head set and the fact that each eye has it's own little monitor. People with VR are glad when they can reach 75 fps. It's very taxing for the system.

That means the FOV is wider = more zoomed out. So how do you manage to spot anything from a distance considering the resolution (per eye) is also lower than any standard monitor these days ?

Quote from former SR-71 pilots : We don't really feel that we fly above mach 3.

The SR-71 don't have a bad FOV, but the pilot can't see below a certain angle due to apex/fuselage shape, and they fly that fast at 25.000 meters, so he just can't see the ground.

In DCS VR if I fly fast at low level above a river passing through a city, something I don't do very often, even passing below a bridge, at full throttle, it's just a feel of LUDICROUS SPEED (+ ground effect shaking the plane crazy), I'm even wondering if it feels really that fast for real.

The lenses make it look more natural, actually VR set has higher vertical resolution on each eye to make it look natural.

I suppose someone with VR set could comment on this. I'm only telling what I've heard about it. :)

It seems that in VR it's not an issue. I wonder if it has to do with the 90 Hz refresh rate. Do you guys actually get 90+ fps in VR, though? And how do you work out FOV in VR?

Well, I think the headset always refreshes at 90fps, but with the rift you usually get "reused" frames at 45fps if you are using their ASW tech which I'd venture to say most users are, but as long as it looks smooth its good. FOV on the rift is 100ish degrees, but you can use the VR zoom to look at either your pit or in the distance, not sure what the final FOV on that is. At any rate it "feels" fast in VR something like a harrier or F5 at low level.

As to the tree size thing, I notice this mostly in the helicopters at low level in VR. I'm not sure if the trees are "huge" but I can certainly hide a gazelle behind a treeline and pop up if I need to.

Yeah people already explained that it all comes with changes of fov. Just to give you an idea about fov, you would need a 75" screen 50cm in front of you to get a fov around 85 which should work quite well out of the box with every module. Than you would have a much bigger immersion and sitting inside a cockpit feeling. This gets better with using nvidias 3d thing, more screens or going directly for VR.

The sense of speed in DCS is very good imo, in all modules , I like the F15 and Mirage, It's a thrill just flying them at low altitude

Marc..

VR is great and all, it's still not perfect for sense of speed.

Rift and HTC is only 110-degree field of view, still missing quite a bit monocular view. New VR with a wider FOV will be much more realistic for sense of speed. pimax is 200 degree.

I posted this in another thread as someone else was asking about it.

https://vr-lens-lab.com/field-of-view-for-virtual-reality-headsets/

So how do you manage to spot anything from a distance considering the resolution (per eye) is also lower than any standard monitor these days

Because it's not - you're forgetting internal the structure of the eye...

The fovea (the part you 'look' with) "comprises less than 1% of retinal size but (is more densely packed with receptors so that it) takes up over 50% of the visual cortex in the brain"

There's as much information in the central 1% of your vision (the bit you look at anything with) as there is in the other 99%.

You have high resolution sensor in the middle of your low resolution wide angle eyes.

Cool! Thanks for the info about FOV and how VR works.

It seems that it might be worth getting the Rift or the original Vive now that prices are dropping. I wanted to go VR at some point anyway, probably 2nd gen, but if it fixes the perception of speed and doesn't really make spotting any more difficult than on a 2d screen then I don't see a reason why not. Plus that amazing feeling of actually sitting in the cockpit.

The topic is drifting away from trees so let me just add that I did some more testing last night, placed several ground units next to trees, compared them to buildings etc. and there's no way they're the right size! At least not most of them. I still think it would help, VR or not, to have trees smaller. I understand why ED went with taller and wider trees (for the same reason they, sadly, removed lots of buildings in the new Caucasus making towns look like villages at best), but just like there's the option of choosing the quality of shadows, draw distance and so on, I'd like to have the option to fly over larger or smaller trees.

EDIT: @Weta43, after some more research I'm reading your post again and I'm not sure if you were just talking about how our eyes work or saying that current gen VR headsets offer higher resolution in the center of the " screen" and lower around the edges. I'm reading about the Vive Pro Eye that's supposed to have this feature which would mean that Vive Pro or Rift don't offer it right now.

FOV and all that, but you are right...the trees are made bigger so the amount of them can be kept lower. There are older threads about this, there was even a mod to make them at a more natural size, but that results in the forests being not that dense.