Share an easy link to this page: edracing.com/ffb

 

 

> G27 information moved to my  Logitech_G27 page (see new notes below too).

 

• Wizards & calibrations on my home page & TWEAKS below it.
• A T300RS forum thread (10/2015) that I don't want to forget (others linked on home page).

 

 

WHEEL CHECK thread is possibly an appropriate place to ask FFB questions.
Use (iRacing Staff) David T's WHEEL CHECK tool in the first post to calculate MIN FORCE setting.
Also read the thread to see what David Tucker (an extremely helpful iRacing staff member) is working on. 

(For reference, link to old wheel check thread).

Wheel profile thread noted further down this page.
My related notes http://edracing.com/g27profile also explains how to create your own (wheel) profile using the Wheel Check app.


"The key between linear and non linear is that in linear mode red is bad and in non linear mode orange is bad on the 'F' meter". (Posted by David T Jan 2016).
Another related post by iRacing staff (David T Sept 2016)
"Orange means you are above about 85% (somewhere around there), red means you are above 100% and actually clipping. Orange is significant because when you are using the default non linear mode then about 85% is when we really start compressing the signal so we can squeeze more in. Anything above that point will have less detail than anything below it.  You want to see flashes of orange, not a steady orange color, think of it as your headroom on a mixer, a little padding so mic pops and other details don't cause clipping. Of course if you use linear mode then just ignore it and make sure you have no red."

 

 

• F9 - FFB AUTO STRENGTH SETTING
  (I'll paraphrase this one day when I have time and patience)  
  
  My excerpt from David's post may be out of context:
  "This is basically baked into iRacing for the next build. You won't get the cool graphs but I keep track of your cars steering torque and calculate the optimal force slider setting from that. You can apply this at any time (once you have half a lap or so of data) by hitting the apply button on the F9 black box, or by going into the settings tab."
  
  From early conversation with David:
  "The profile (mentioned below) straightens out your wheel so that it is linear, this adjusts our forces so that 100% in the sim is 100% at your wheel (well something like that)  Together they give you the optimal setup."
  
  "Basically there is a new ‘apply’ button in the F9 black box and in the wheel settings tab, both next to the force setting. This button will appear after you have put in so many seconds of a clean lap (no off track, no hitting things, etc).  Hitting the button will apply what I calculate to be a reasonable number for the force slider.  The number becomes more reliable the more you drive but I wanted people to be able to sort of dial things in without doing 4 laps at the Nuremberg ring.  The button will appear again whenever the calculated force is sufficiently different from the current setting."
  
  "Right now it is all triggered off of time, you need to put in 30 seconds of driving to get the button to show up (it only shows up if the numbers are different as well), so on a small track like south boston it can take a few laps"
  
  "Auto detect the optimal force feedback force level based on your driving. Simply hit the 'auto' button found in the settings tab or F9 black box after driving a few laps to apply the detected force levels."
  
  
• It's now posted with the release notes (by David T):
  "I forgot a release note. I added in code to auto detect the optimal FFB force slider value. Go out and drive a lap or two in your favorite car and watch the F9 black box. At the bottom, where you can set the FFB force an 'auto' button will appear if I determine that your force setting is not optimal, click on that at any time to apply the new value. There is a similar button in the settings dialog that lets you apply it from there.
  Ideally you would drive a clean lap with no off tracks or curb strikes, but I have code in place to try and filter out those cases so it should work reasonably well no matter how you drive."
  
  
• David T excerpts from thread:
  "Sorry, I had marked my checkin as 'not for members' because I checked it in at the very start of this season and I did not want it to get pushed out in a maintenance patch. I guess someone took that to mean don't mention it in the release notes. Its my fault for not checking 
  
  This feature is simple. You go out and drive like you always do and I constantly keep track of the forces coming from your wheel and try to estimate what a good peak force value would be. I tried to make this smart so that bangs and bumps don't affect the number and neither do off tracks, but of course there is only so much I can do there.
  
  If I detect that the force slider is set different than my estimation of the optimal number then the auto button will appear and you can click it to get the new value. I don't auto apply because I don't want your wheel to be changing on you as you drive, that would be bad. Anyway take this as a great starting point, but feel free to go down (or up a tiny bit) from there.
  
  This does not replace the min force slider. Min force adjusts how your wheel reacts to small forces, this adjust how the force is spread out over your wheels full range. The new wheel profiler code replaces the min force slider and that is the route I recommend going, if you can get your hands on a cheap usb scale. http://members.iracing.com/jforum/posts/list/3482238.page.
  
  Together this auto button and the force profiler should take care of all of the quirks in your wheel and give you the most linear output."
  
  "One interesting feature is that this makes it simpler to move back and forth between linear and non linear mode. As soon as you switch between linear and non linear (assuming you have put in a lap or two) the auto button will light up. Stabbing it will set the slider so it feels about the same as in the previous mode. I find that this does a better job of keeping the forces feeling about equal, much better than my original mapping that makes linear mode feel too soft."
  
  "It can be used for any wheel that has less torque than the car you intend to drive. Most cars produce between 10-30 Nm of torque while most DD wheels tend to be in the 10-30 Nm range as well.
  So you have to decide how you want to setup your DD wheel. Do you set it 1:1 (assuming you know the torque of your motor), or do you set it up in a 2:1 ratio (setting the sim to 40 Nm peak) so that all cars (most cars) work without needing to adjust anything and without risking clipping, or do you adjust it on a per car basis without letting the adjustment go below your wheels peak torque.
  Basically put the sim into Nm mode, run this tool and let it apply, and if the number given is less than your wheels output then set the slider back up to match your wheels peak torque."
  
  "If sim commander takes control of our FFB settings then this gets shut off along with everything else. If sim commander is setup not to take control then this works just like with any other wheel.
  Sim commander takes this idea to the next level and averages data across multiple customers to give you good wheel settings out of the box so there is no need for it if you let sim commander do all the work."
  
  "I leave a bit of headroom, enough for you to feel the curb strike or a particularly jarring bump."
  
  
• David T post in Wheel Check thread:
  " if you are already running at 1:1 then you don't need to adjust the force slider.
  In an ideal world I would know the peak force that your wheel can output and I would never adjust the slider beyond what your wheel can produce. However with all the OSW wheels out there using different motors and settings it makes it all but impossible to auto detect a wheels peak force. I actually started down the road of automating this but quickly realized that the only wheels that could really use this feature were the ones I could never auto detect..."
  Another post "I just tested it out, by default hitting the space bar when the force is selected will click on the auto button. I usually map that to the button under the thumb-stick on my CSW wheel rims."
  

 

 

• Wheel oscillations are now dampened when parked. A new friction damper is applied to the wheel at speeds below 15 mph.
  The force level is also reduced by 50% if "Dampen Oscillations" is checked in the options screen.
• The wheel oscillation damper can be tuned by adjusting the values in the "app.ini" file for the [Force Feedback], including: steeringDampingFactor=0.05, steeringDampingParkedMaxPercent=0.20 and steeringForceParkedPct=0.50. Stronger wheels may need to reduce steeringDampingFactor, while weaker wheels could adjust steeringDampingFactor to as high as 0.10. In general, you may not need to change this.
• The old damper has been replaced with our new friction damper. Now adjusting the damping slider in the settings tab sets a cutoff for the maximum amount of force that the damper can apply to your wheel. For gear driven wheels, a value between 5% and 20% will add a sense of weight to the wheel without greatly affecting the overall force feedback feel. You can return to the old damper behavior by editing the "app.ini" file and setting [Force Feedback] dampingSliderSetsFriction=0, when the damping slider is set to control the old damper then the "app.ini" file setting [Force Feedback] steeringDampingMaxPercent=0.0 controls the new friction damper.
  

 

 

FFB changes 2016s1.  Notes sourced from David T iRacing Staff (02.12.15).

 

Sourced from conversation with David:
There are only a few changes this season.

By default now, steeringDampingMaxPercent is ignored and instead we use the damping slider value from in the sim to set this value so that you can activate the friction damper from within the sim. 
You can revert that back to the old behavior by setting dampingSliderSetsFriction=0. 
By default this also removes the baked in damping effect from your wheel, which most people did not use anyway.

There are also new values steeringDampingParkedMaxPercent=0.20 and steeringForceParkedPct=0.50 that turn up the damping and down the forces when your car is going less than about 10 mph in order to remove the runaway oscillations that some cars experience when parked.  This can be turned on and off in the UI with the new ‘dampen oscillations’ checkbox.

Everything else remains the same, but hopefully you won’t need to mess around in the app.ini as much with the above changes.

---

Post by David:
Q: David, will the oscillation filter make it to the new build?

Yes it is in the new build and activated by default. There may be some wheels that this causes troubles with, but I only heard a few quibbles from the testers, overall they loved it. If you do find that your wheel shakes when parked then try turning off the anti-oscillation code and see if that helps.

I also cleaned up my new friction damper and made the damping slider control that by default. There is an app.ini option to go back to the old damping mode if people miss it, but the new damper should behave the same on all wheels and it actually does something useful on lower end wheels like the g27. On those wheels it adds weight to the wheel making it feel like a more expensive model. Between this and min force you can almost make your G27 feel like a $500 wheel.

In post David notes: Take the defaults for everything but add in 10% damping and 10-15% min force (13 on my wheel) and you are done.

In a reply to me, David also noted: The 10% damper with the G27 is down to personal preference.  I like the feel, it makes the wheel feel more like my real car, but it has no other benefit than to make your wheel feel a bit less plasticky.  With belt drive wheels there is little need for the damping slider since there is already too much damping provided by the belt.  With the direct drive wheels the forces are immediate enough that the wheel never feels disconnected or floaty so again there is no need for the damper.

Post by David:
For this season (2015s4) you can mess with the tweaks in the ini file, but next season (2016s1) they all go away, well get replaced with the new damping slider and dampen oscillations checkbox. Since we are only a week away from the release, I would not mess with the ini at this point in time.

If you have already played with the ini file, you can always just delete a line (or block of lines) from the file to force us to reset the value to its default. So in this case just delete the whole [Force Feedback] block, or you can just remove the app.ini file completely if you want to reset all settings to there defaults.

The defaults change from time to time in the app.ini and renderer.ini files, it is not a bad idea to back up those files after the season change over and let us recreate them for you. That way you get the latest settings for everything (especially graphics). Season to season not much changes, but if you have the same files from 2009 then it is probably time to give it a reboot.

From there you can use my favorite diff utility, http://kdiff3.sourceforge.net/ and check what has changed over the years.

Post by David:
Q: David, is the oscillation filter speed-dependent?

Yes, it only kicks in when you are parked 

I don't currently attempt to do anything about oscillations while driving. Usually those are caused by improperly configured wheels so it would be counter productive for me to filter them out. On really strong wheels you can still get oscillations even with everything setup right, and on really tight cars as well, but that is not all that easy to filter.

Instead what I do is ramp up a damper and down the FFB force when you slow to a stop so that our parked tires don't cause a runaway oscillation. This seems to work fairly well, even if it is not really the right way to fix the problem.

---

G27 users also see Logitech_G27 for 2016s1 changes

 

 

2015s4 FFB changes posted by David T in thread.

 

I did make a change in the FFB code this season.
Now when a wheel disconnects and reconnects I attempt to find its old descriptor and only reinitialize that device, without tearing down all the devices and bringing them back up.
This is not perfect, it can be fooled if you have two of the same device plugged in (say you have 2 custom button boxes with identical controllers), but I try to detect that situation and deal with it.

Anyway if you suspect that this code is giving you troubles, you can go back to the old way of doing things. Set the following in app.ini [Force Feedback] initOnlyNewDevices=0 to go back to the old code.

It is also very likely that if a device resets itself due to a flaky cable that it will show up with a different instance id, as if it was a second device being plugged in. I can't work around that, you just have to unplug and replug the wheel to get windows to force it back to the first instance id. That is the way it has always been, so nothing is new here.

With the new EAC cheat detection we have to launch iRacing inside of a sandbox that is controlled by EAC. For now our simple solution is to launch iRacing twice, the first time just sets up EAC to launch the second instance and then quits.

To external tools, like the logitech profiler it just looks like iRacing started up and shut right back down, so the profiler falls back to its default profile (whatever you set that to). For now the workaround is to just setup the default profile to be your iRacing profile, that way when it falls back to the defaults, nothing changes.

The profiler has its little quirks but we don't do anything special to accommodate it. Really the biggest issue is that some previous version of the profiler left corrupted profiles on disk after an update to a newer version so a lot of long standing customers have flaky profiles. The fix there is to clear out every last bit of the profiler, including any files left over buried in the documents folder and reinstall the profiler. After that everything seems to work really well (well up till this release...).

I don't recommend using the profile feature of the profiler, that seems to be the source of most issues. If you only use the default profile then it never seems to cause any issues. Of course that removes 90% of the profilers purpose.

 

 

Notes from David T's post June 2014 relative to all wheels.

Set up iRacing with the following values:

- (See 2016s1 notes) Damper set to off, you don't need this. It is only left here because it was there in nascar 2003.

- linear force unchecked. You don't need linear force unless you have a super fancy wheel

- You can use the 'F' meter while driving to see how close the FFB forces are to saturating (it turns yellow when you get close, and red when you saturate or clip). And you can use the F9 box to adjust the force level while driving as well. I like to set the force as high as I can without saturating, but some drivers like less force, the key is to not saturate or the wheel will feel lifeless.

- Min force attempts to correct a flaw (or feature, it is intentionally put there) in some wheels where the wheel will not react to our FFB commands unless the force goes above some minimum amount. If min force is set too high, then the wheel will chatter when driving straight. So the simplest way to set it is just to try 10% and then 5% or 20% depending on if the wheel chatters or not, going back and forth until you get close enough to a reasonable number. You can also dig out wheel check and do some work to figure out the exact number, but in general you don't need that much precision, getting to within 5% of the correct value is probably good enough.

On top of all of that there are two parameters in the [documents]|iracing|app.ini file that you can mess with.

[Force Feedback] steeringFFBSmooth=1.0
This applies some smoothing to the FFB output, and is the only good way to stop a car that chatters too much from banging your hands to pieces. Damping will only make the problem worse, so use this instead. However before you apply smoothing make sure you are not overdoing it with the min force slider. The number is an odd one, you want to set it to 1/n where n is the number of samples to smooth, so 1/2 or 0.5 smooths two samples, 1/3 or 0.33 smooths 3 samples, 1/4 or 0.25 smooths 4 samples and so on. Going much past 1/5 or 0.2 is only going to add latency and not improve things at all for you. Oh and the default of 1/1 or 1 means one sample, or no smoothing at all.

(See 2016s1 notes) [Force Feedback] steeringDampingMaxPercent=0.0
This is an experimental friction damper that I added in a season or two ago. It works really well on the G27 wheel to give it some weight and make it feel less plasticity, however it does not do much for belt driven wheel since they already have plenty of mechanical damping from the belts. Try a value of 0.2 and go up and down from there as needed.

 

 

Source: iRacing 2014s2 release notes.
This works best on lower end wheels.
New experimental 'friction' damper to add a weight feeling on your wheel.
The damper provides a small amount of resistance to wheel motion no matter how slow or fast you move the wheel.
To utilise this, edit app.ini:
[Force Feedback] steeringDampingMaxPercent=0.0 to a value between 0.05 and 0.30
Ed: don't edit the above setting, see 2016s1 notes
My preference was SteeringDampingMaxPercent=0.2, 2016s1 it's the same as setting the Damping slider in sim options (not profiler) to 20%
If this becomes unstable then adjust app.ini [Force Feedback] steeringDampingFactor=0.10 to a smaller value but you should not need to adjust this at all.

 

Follow up information from David T, source: forum post.
The friction effect consumes your FFB headroom as indicated by the number (0.05 being 5% and 0.5 being 50% of the head room).
I'm still digesting this...
All force effects will be added together with the friction effect.
Bumps and rumbles will still pass on through, but they may end up being relatively small compared to the overall force of the friction effect.
This is in complete contrast to the default damping effect that increases its force the faster you turn the wheel.
In that case any large bump is automatically dampened out while little rumbles get passed on through (like when your wheel oscillates down the straight away).
So the short answer is that using a little bit of this (say 10%) will only have a small impact on the force you feel while having a large impact on how cheap and light your wheel feels.

 

 

• Related wheel noise:
Using "steeringDampingFactor" may induce a small noise from wheel (reported on forum).
David T reply post: The noise is a side effect of the PID loop that creates the friction effect. You can turn down steeringDampingFactor=0.10 to something like 0.05 if you want to reduce the noise, but you probably can't eliminate it. Also be sure you are applying min force properly, that will make sure that the damper can work optimally. On a G27 wheel you want to run about 10% min force, or you can run wheel check to get a precise number. If your's is 22% like mine, wheel check is a better idea! Wheel check is linked & referenced on the first page of the FFB thread.

• Old notes

• 2014s2 linear vs non linear the debate: forum post | screenshot.
• 2014s1 FFB linear / non linear - screenshot (source p52 of forum thread).
• 2013s4 FFB update - screenshot. 

 

 

• Clayton's locked/old FFB thread has some great info buried within.
It's now a locked thread loaded with many terrific posts.
(Doesn't include changes deployed 2016s1 12/2015).

 

Another FFB thread with some informative posts (May 2015) - check for relevance to 2016s1 build.