Like your FFB strong? Think again..

[Niels_at_home]

Heyas,

I've been around this simracing scene now forever and it seems the vast majority of folks like to run very high force feedback settings. Then you often read claims how great it feels and how they can even feel the effect of flies building up on the windscreen through these FFB settings (sarcasm = on). Some even feel when the coffee is done in the kitchen (sarcasm = still on)..

Force Feedback talk
Good sims will use complex physics engines to calculate the force feedback. Part of the feel is the tires, part is the suspension geometry, and this all changes with steering angle and things like how much weight (load) is on the tires.

If you'd only feel the tire part of the force feedback, the forces would be near ZERO by the time you've applied the optimum steering angle to get maximum grip. Thats just how tire physics (pneumatic trail) works, give or take some margins. Counter intuitive eh, but its often near true!

Suspension geometry usually adds a chunk of force, but still it is higly likely that the force you feel in a racing car drops off after a certain amount of steering and by the time you've applied the optimum steering angle for max grip, force through the steering wheel might be about half of the maximum.

That means when the steering goes light in a racing car, you might not be understeering at all, you might be right at the maximum grip levels!

Problems with sims
Even when your favourite sim has good tire and suspension physics, that doesn't mean your wheel (G25, Fanatec, Thrustmaster etc) will behave properly. The physics engine will just calculate a torque or a steering rack force, perhaps during a lap this value is between 0 and 5000 Newtons.

At some point the sim will have to tell your FFB steering wheel what force it has to apply. You can imagine there is some scaling required. Ideally the 0 .. 5000Newton that occur on the track should be the range where your FFB wheel responds between 0% and 100% of its capable force.

This scaling is NOT DONE AUTOMATICALLY by iracing / LFS / rFactor&Realfeel !! You have to scale this yourself. In iRacing and LFS its the force feedback strength in the menu, with rFactor&Realfeel there is the realfeelplugin.ini 'Max Force' entry to adjust.

When you scale the forces down too much, you get weak force feedback. When you don't scale them down enough, you're asking more from your wheel than it can do, so at some point the forces will be trimmed. This is called 'clipping'. If your wheel has a maximum of 100, you can't make it do 200. So anything you ask from it above 100, you won't feel a difference.

First chart: Scaling the force feedback

The blue line is how a good simulator might calculate the force feedback strength versus your steering wheel angle. It is what it *wants* your FFB wheel to do.

Lets say proper scaling means you have to run the ingame FFB strength at 20% which is not uncommon at all. In this example, 20% strength matches the maximum occuring force feedback of the physics engine to the maximum feedback your wheel can put out.

If you'd use 100% ingame FFB strength, you would only have a small part of the desired curve fit below that line. That is bad.


Second chart: Results

This chart is the results; what YOU feel on your wheel. You can see that running 100% FFB strength tries to make your wheel 5x stronger than it really is. It just can't do it, so you feel the red line. Apply steering, forces max out *very* quickly, and as you steer more, the force stays maxed out. It hasn't got the power to follow the desired dotted line. This is what many simracers do probably without knowing it. The force feedback isn't detailed at all, its almost on/off.

The green line is what you get with proper scaling. It follows the desired shape exactly, but now with the maximum occuring force nicely matched to your wheels maximum deliverable force.

Now why does 100% still feel stronger than 20%, despite the maximum force being the same? At 100% you have to grip the wheel like mad because any slight bump or minimal steering will result in maximum force. Once you're steering, the forces are mostly constant, but going near straight you feel strong jolts left/right as micro bumps / steering inputs cause these forces. Wheels setup like this are often unstable and will oscillate when you let go of the wheel on the straight. For some reason lots of folks think this feels good.

So how do I set this up correctly then?
Thats the hard part. Even on the same car if you change the car setup (caster, downforce) the numbers will change. On a flat street circuit the values will be different than in a fast banked oval.

Realfeel with rFactor is the easiest, you can drive the car on a track, look at the telemetry, and the 'Steering Arm Force' that you see in a hard corner is your desired Realfeel.ini "MaxForce" entry. Don't look at short spikes of force, go for a sort of average force you see in a fast bend.

With other sims its a matter of getting a feel for what your wheel can do. Once you know what its maximum strength feels like, lower the ingame FFB strength until you clearly are below this maximum force. Then add force slowly until you get to the point where it seems saturation occurs. I can't help much, the FFB strength will typically be between 1% and 100% :S. Try the maximum force in a steady corner, because on a straight, the sudden left/right jolts of too strong force feedback will make it feel subjectively stronger than it is.

Conclusions?
Current wheels like the G27 are fairly weak; they can't really deliver a strong force. It is very easy to try and ask too much from the wheel. It might also lead to overheating and faster wear!

I've tried to show you what force feedback scaling does and how running too strong force feedback settings can numb down the detail you feel, even when it *seems* like the effects are nice and strong.

Everybody is free of course to use whatever setting they like, but at least this shows that people running very high FFB strengths claiming they get lots of detail and a good feel for the car, are wrong from an objective point of view.

 

[isamu]

Very good info Niels

 

[Bert van Jaarsveldt]

Anyone tried settings for T500RS in rfactor1 and RF2?

 

[Eric Bergeron]

Very good info Niels , it's an others reason why we like GSC !

Thanks !

 

[Den.]

Thank you Niels. Very handy info.

 

[townnet]

I heard that some Fanatec CSR elite user get motor failure issue, is because they set ffb to very high?

 

[Blkout]

No it's because, the motors are not adequate for the task.

 

[tutubra]

Hello all, I know this thread is kind of old, but it seems the best one around about FFB.
I got a G27 one month ago, my first wheel, and have both GSC Extreme and Formula Truck. If I really understood what Niels and Mizoo stated, in order to reduce clipping I should increase the maxforceatsteeringrack values in the RealFeel ini, right?

In GSCE, I noticed some cars, like the stock, have negative values on this parameter, and others, like the kart, have postive values. I have then two doubts:

- When you say to increase this value, in case of negative values, I should move them closer to zero, or consider only the number?
- When a car has a positive value, should I turn the ingame FFB to positive value too?

Thanks very much.

 

[Terry Rock]

There seems to be several beliefs in simracing, which translate into some rather serious flaws.
FFB is one of them.
Having tracked a Porsche 993 for about three years...driven too many rally events to count...driven a Chevron B16 at speed....driven laps in a Formula Ford, plus years and years of Karting, I've covered the entire spectrum on both dirt and asphalt.
None of those feel like they want to "rip your arms out"....and yet, we have guys who turn everything up to max and claim how 'believable' it is.
I usually have a good 'chuckle'. If only they knew.
The other thing I've noticed in simracing, is that older models of cars are not 'pointed' or precise in their handling.
Most developers tend to give a car which wallows all over the place, then claim the older tire technology of that era as the reason.
Nothing could be further from the truth in some cases.
I've driven a lot of cars at speed...both road and race. Most were quite good.
Braking is another area where game makers fall down...a lot.
Track cars...even older one generally have phenomenal braking ability.

 

[Kjell Eilertsen]

There seems to be several beliefs in simracing, which translate into some rather serious flaws.
FFB is one of them.
Having tracked a Porsche 993 for about three years...driven too many rally events to count...driven a Chevron B16 at speed....driven laps in a Formula Ford, plus years and years of Karting, I've covered the entire spectrum on both dirt and asphalt.
None of those feel like they want to "rip your arms out"....and yet, we have guys who turn everything up to max and claim how 'believable' it is.
I usually have a good 'chuckle'. If only they knew.
The other thing I've noticed in simracing, is that older models of cars are not 'pointed' or precise in their handling.
Most developers tend to give a car which wallows all over the place, then claim the older tire technology of that era as the reason.
Nothing could be further from the truth in some cases.
I've driven a lot of cars at speed...both road and race. Most were quite good.
Braking is another area where game makers fall down...a lot.
Track cars...even older one generally have phenomenal braking ability.

According to you, which are the more believable Sims out there (when dialed in correctly)?

 

[Terry Rock]

@kjell....
There is no one sim I've tried in the last ten years which represents the most accurate.
They all seem to have individual bits and pieces which excel over each other.
They're even cars within individual sims which trump others...one will feel authentic and another will just be downright unbelievable.
I have not tried I-racing (so I cannot comment on that)...but the feeling on turn in to corners in AC coupled with the road feel on straights in RF2, then take the overall frequency down a notch, would get you close.
It's amazing how much as a driver you can 'stretch' tires...even road tires.
As far as outright feedback is concerned, the 'sharpness' felt in sims (i.e..as in feeling every single bump in the road) is vastly exaggerated. You do 'feel' the road and it's changes obviously...but it's just one or two 'ticks' up from your road saloon in frequency.
You become more aware due to the lack of sound deadening material in the chassis.

 

[tutubra]

Thanks Terry for all the info. Besides driving my normal car around normal roads, and doing some karting, I have no experience in real-world racing.

I really like the physics and feel of GSCE, better than AC, IMO. Can you or anyone help me with my doubts about FFB and RealFeel?

 

[Dynamitry]

In GSCE, I noticed some cars, like the stock, have negative values on this parameter, and others, like the kart, have postive values. I have then two doubts:

- When you say to increase this value, in case of negative values, I should move them closer to zero, or consider only the number?
- When a car has a positive value, should I turn the ingame FFB to positive value too?

The positive-negative value of MaxForceAtSteeringRack depends on the steering arms location of the physical model, if the steering arms are in front or behind the front axis.
You can increase the number to get stronger feedback, lower number to decrease strength, but don't change the polarity of GSCE RealFeel.ini (and make a backup before you touch it).
I'd suggest not to mess with GSCE RealFeel values too much as it comes polished from Reiza.

The ingame polarity of FFB force depends on wheel, I don't remember exactly how it works, but if you set incorrectly and compensate it by changing RealFeel FFB polarity, you will get reversed FFB effects (not the steering FFB forces, but the artificial FFB effects). So for your question - the ingame FFB strength polarity has nothing to do with MaxForceAtSteeringRack polarity.

 

[tutubra]

Thank you very much Dynamitry! Everything you said is right, I did some testing. In the end, I did what Niels first suggested, ran some laps with telemetry and adjusted the MaxForceAtSteeringRack using the value of Steering Arm Force at MoTeC.

Now my FFB is weaker but gives more information about the tires. Before it was only providing wheight to the wheel.

 

[assettonoob]

Clipping is really important but there are other problems:
The one thing not mentioned in the article at the beginning of this thread, is that it's really important to adjust the feedback to where it gives the most linear increase and decrease in torque. This varies from game to game! At least the Accuforce people developed 'simcommander' to try to solve the problems this causes.
If you adjust the feedback to a point higher than the developers assumed you'd use, it will have a ridiculous amount of FFB increase and decrease that will not be proportional to real life.
Example developer sets aligning torque graph to be 'accurate' at 50%, and give a linear increase. If you are using an FFB wheel at 75% the steps between the torque on the wheel become 50% larger!
Oh dear. That's assuming the wheel even outputs 50% more torque, and the actual torque response of the wheel for different inputs varies. This is I think why some wheels on the market are 'linear' in their force feedback responses and some aren't. It's all in the software programming as developers apparently just give values, not calculated torque outputs. This is a major problem with all FFB without using the correct software to solve the FFB output torque problem.

The software for an FFB wheel should know the exact torque output for all speeds, loads and output on the motor. Using real tyre self aligning torque values as a basis, it should adjust the wheels torque to be proportionally accurate, and not let the user muck it up by adjusting it! If a wheel blindly outputs the % FFB values the developer gives it, then it's not accurate at all.

Half the problem with FFB is that the developer doesn't know what wheel or settings the user is using! Even when you have one 'official' wheel like Forza on the Xbox One, it's still difficult to translate real torque values to the wheel if the user can adjust the force feedback strength.

 

[Tnadz]

More like compression or limiting used in mastering music where the quitest passages are made louder and the louder passages quiter which creates a clipping effect and destroys the dynamics and air of music.You can tell when this effect is on by the muddy ,messy,distorted quality of the production and by looking at your metres.With over compressed music,they hardly move.All in the name of being louder on the radio.Progress?What progress?

Perfect example of what's going on here. That's why classical music is so impressive. You have to raise the volume to make those nearly inaudible sections heard but then when the big hits happen, they nearly blow your ears out. You've simply raised the sound floor without affecting dynamics*. However, if you're speakers (what would be the wheel) don't have the range to produce that output, you'd still get clipping. The metaphor translates to fatigue also. When the wheel is constantly giving overcompressed data and running the feedback at maximum the whole time, your arms get tired the same way your ears start wearing out or even hurting when listening to pop or rock music set at even a moderate level. Awesome.

 

[Tnadz]

Alexander Rhodes touched on it briefly describing off-road feedback but no one has really mentioned how a lot of the actual force feedback from the car comes through the seat and the forces imposed on the driver. Granted it might be outside the scope of this discussion, but I feel it's worth mentioning, especially for the (albeit small) population of simmers who use motion chairs. Obviously with the introduction of these other forces, specifically traction-loss, there's a lot more feedback introduced to simulate this effect and the wheel doesn't have to do double duty to create artificial forces. Tech advances have created a lot more consumer grade products at reasonable prices and even DIY kits/parts are becoming more accessible.

 

[assettonoob]

Alexander Rhodes touched on it briefly describing off-road feedback but no one has really mentioned how a lot of the actual force feedback from the car comes through the seat and the forces imposed on the driver. Granted it might be outside the scope of this discussion, but I feel it's worth mentioning, especially for the (albeit small) population of simmers who use motion chairs. Obviously with the introduction of these other forces, specifically traction-loss, there's a lot more feedback introduced to simulate this effect and the wheel doesn't have to do double duty to create artificial forces. Tech advances have created a lot more consumer grade products at reasonable prices and even DIY kits/parts are becoming more accessible.

I mention this far too much, but I think just simulate the car body pitch, roll and height relative to flat ground. Forget simulating G-force and 360 rotation it's too expensive, just move the body or head exactly with the height, pitch and roll angle of the car body. Active cameras that move exactly with the car body motion relative to flat ground would also help, but may cause motion sickness?
Perhaps the cost and driving benefit, wouldn't be as much as I hope it would.

 

[Tnadz]

I don't know, there are quite a few people who have made fairly robust systems for only a few hundred dollars. And you can start to find basic yet fairly decent systems out there for not very much. Coupled with something like the Rift, this type of system could do a lot to fool the mind into motion without having to violently throw you around the room or cost a fortune. And to stay on the post topic, it could take that workload away from the wheel so it can behave more like a wheel.

 

[Spinelli]

Thank you very much Dynamitry! Everything you said is right, I did some testing. In the end, I did what Niels first suggested, ran some laps with telemetry and adjusted the MaxForceAtSteeringRack using the value of Steering Arm Force at MoTeC.

Now my FFB is weaker but gives more information about the tires. Before it was only providing wheight to the wheel.

Can you explain this procedure? I noticed that all 3 wheels I've recently tried in SCE - the TM T500RS, TM TX, and my current wheel the Fanatec Clubsport Wheels V2 - don't really give me much details in forces. Ok, sure, I get self aligning torque (when the wheel turns the opposite way to sort of help you correct oversteer), and I get resistance when turning into a corner, and I feel undulations of the road nicely - like bumps and such - but in terms of grip, especially front -end longitudional and lateral grip, I feel nothing.

With all 3 wheels (TM T500RS, TM TX, Fana CSW V2) I hardly, if at all, get any difference in FFB from when my front tyres have full grip (let's say front wheels pointed completely straight), to when they are maybe slipping just a touch, to when they are slipping a good amount and near optimal slip/grip, to when I start going over that optimum slip anlge, to when I start understeering a fair bit, to understeering like crazy

There is almost no difference at all in all those situations relative to eachother. It's just plain resistance, bumps, and self-aligning torque. Hardly any informative FFB info.

Editing the controller file and combining that with medium/high/full FFB affects, and then setting RealFeel to 80% or 90%, seems to give me a lot more different FFB communication depending on all sorts of different lateral and longitudional grip/slip but I want to try to get those same connected, detailed, and highly informative FFB cues with set to "low" since apparently "low" is the purest.

How do you use telemetry software to figure out what settings to use with RealFeel??

 

[bluey]

please excuse i am getting a little lost in all this i have t500 do i set the profiler at 100% then in game at50%and start from there or start profiler a 50% and in game at 50% as a starting point help as i am new to sim racing my sims are ac re3 and soon gsce