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All you need to know regarding FFB (If you have time) haha!

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All you need to know regarding FFB (If you have time) haha!

Post by Guest on Wed Feb 22, 2017 2:43 pm

Tire Force (Tire Force)
FORCE FEEDBACK CALIBRATION

This is simply an overall multiplier on all of the input tire forces. Note that G forces, the input to Gut, are not scaled with this parameter. Use this parameter to scale for a controller overall. Use SpindleMasterScale to scale per car or setup.

Spindle
EDIT TUNING SETUP / FORCE FEEDBACK / SPINDLE

SpindleMasterScale (Master Scale)

This is a multiplier on all of the front tire forces. This was added to allow the following four scale to default to 1, and be more intuitively like “weights”.

SpindleFxScale (Fx Scale)
SpindleFyScale (Fy Scale)
SpindleFzScale (Fz Scale)
SpindleMzScale (Mz Scale)

Individual scales on the components going through the spindle/rack. To get pure rack forces, leave these all at the same value. 1.0 is a convenient value for this, and use SpindleMasterScale to dial overall spindle force.

SpindleFxLoPass (Fx Smoothing)
SpindleFyLoPass (Fy Smoothing)
SpindleFzLoPass (Fz Smoothing)
SpindleMzLoPass (Mz Smoothing)

Individual smoothing on the components going through the spindle/rack. Typically Fx requires more smoothing than the
others. 0.0 is no smoothing. 1.0 is normalized to “really smooth but still some useful signal”. Values above 1.0 are valid.

SpindleArm (Arm Angle)

SpindleArm is the angle, in degrees, of the attachment of the tie rod to the spindle. Zero degrees means the tie rod is attached directly aft of the axis. That particular distance, how far aft, is not critical, because that just amounts to scale, which we adjust based on squeezing into the device range anyway. The angle though matters a lot in how the forces feel when the steering wheel is not straight.

90 degrees is then with the tie rod directly inboard of the axis, which physically would result in the inability to steer. Realistic values I'd guess are between 0 and 45.

Note that the per force Soft Clippers from Topology 2 have been removed. This is one of the adjustments to make FFB control completely from the GUI reasonable.


Seat of Pants (Sop)
EDIT TUNING SETUP / FORCE FEEDBACK / BODY & SOP

The basic idea of “Seat of Pants” is to present information from what is happening at the rear of the car through force feedback. There are two physical forces that are used. The rear side loads and the rear vertical loads.

SoPScale (SoP Scale)
Overall scaling of Seat of Pants

SoPLateral (SoP Lateral Scale)
Scaling of the rear side load effect.

SoPDifferential (SoP Differential Scale)
Scaling of the rear vertical load effect, which is actually the difference between right and left vertical loads.

SoPLoPass (SoP Damping)
Smoothing of the Seat of Pants signal. 0.0 is no smoothing. 1.0 is normalized to “really smooth but still some useful signal”. Values above 1.0 are valid.


Relative Torque Adjust
FORCE FEEDBACK CALIBRATION

This is an all new concept for Topology 3. The idea here is to present torque to the wheel based on the change in torque through time instead of as absolute torque. This means that with reasonable parameters, the wheel will never fully saturate. But unlike soft clipping (which can also prevent saturation), the high end torques do not get as heavily squeezed.

There is one side effect to tune out though, and that is the wheel losing center over time. If all torque was completely via “Relative Torque Adjust”, centered torque would move around as the wheel goes through previously saturating torques. To prevent this, we use the bleed value to “bleed” absolute torque back into the mix.

RelativeGain (Relative Adjust Gain)
This is the scaling on the amount of calculated torque change that is applied. 1.0 is the intuitively correct value. 0.0 turns this component off.

RelativeBleed (Relative Adjust Bleed)
This is a time value for bleeding absolute torque back in. 1.0s is a good starting point.

RelativeClamp (Relative Adjust Clamp)
This is the force to wheel value (so in the 0.0 to 1.0 range) where the non absolute running magnitude is clamped. This does not clamp the overall value, and torques can still go above this, but it does exert a strong clamping effect. 1.0 is a good starting point for this. Values greater than 1.0 can make sense if soft clipping is also used. Values less than 1.0
makes sense to give some headroom for spikes to be a little more symmetrical around the clamp.

Note that with this component on, and with clamp at 1.0 or less, and not too much bleed, there is no full saturation. What this means is that what was too much force before now becomes more force effects felt near full force. But this too can become too much, as that can start to overpower the more subtle unsaturated force range. So you still need to dial overall force (via Tire Force and the scales), but that scaling can become an interesting control, not just something to avoid saturation with.


Gut Simulation
EDIT TUNING SETUP / FORCE FEEDBACK / BODY & SOP

This is a simulation of the G forces on the body of the driver. Basically, G forces move the body around via a physical simulation, and the result of that simulation is translated to force feedback.


GutScale (Body Scale)
Magnitude of the gut simulation in FFB. 1.0 is normalized to “significant but not overpowering”.

GutLongScale (Body Longitudinal Scale)
Magnitude of longitudinal effect applied. This is a scaling of the baseline lateral effect. At 0.0, the gut effect will be all based on lateral G’s. With non zero GutLongScale, under braking G’s, the lateral effect will increase, and under acceleration G’s the lateral effect will decrease.

GutMass
This is the mass of the simulated “gut”, which should not be the whole human body. It should
be some lesser portion, roughly being the effective amount of mass not “locked down” rigid by the seat and seatbelts. This is a very fuzzy concept, so the number is really just a very rough ballpark number. This is fine, because the simulation is not overly sensitive to this number. It matters, but it is not extremely critical.

The default is 50 kg.

GutStiffness (Body Stiffness)
Stiffness of the gut with respect to the car. So in a kart this may be lower. In an F1 car this is probably pretty high.

GutDamping (Body Damping)
This is a multiplier on critical damping of whatever mass and stiffness is set. Therefore, 1.0 means exactly critically damped.


Arm/Linkage Simulation
FORCE FEEDBACK CALIBRATION

The arm/linkage simulation simulates that the wheel is driven by a non rigid linkage, namely the driver’s arms, as well as play and mass in the linkages themselves.. However, this is done purely with force feedback. The position of the the controller still directly dictates the location of the simulation wheel.
This simulation also serves as the main global smoothing stage.

ArmScale (Linkage Scale)
Ratio of incoming signal to pass through the arm/linkage simulation. 0.0 if off. 1.0 is application of all incoming signal.

ArmMass
Mass of “arms”, with respect to simulation. This does not necessarily mean the average mass of two human arms. This is the effective mass with respect to the degree of freedom that is the wheel/controller.

ArmStiffness (Linkage Stiffness)
Spring­like stiffness of the “arms”. Stiffer settings will pass through higher frequency information. Softer settings will smooth more.

ArmDamping (Linkage Damping)
This is a multiplier on critical damping of whatever mass and stiffness is set. Therefore, 1.0 means exactly critically damped.

Soft Clipping
FORCE FEEDBACK CALIBRATION

This compresses all force within range of the wheel, although the stronger the force, the more it is squeezed into the higher force range. In some ways this is like Log Scaling in previous topologies, but Soft Clipping guarantees all signal will squeeze into the range, however compressed. On the other hand, approaching linear behavior is not implicit with soft clipping, as it can be with log scaling.

SoftClip (Soft Clipping (Half Input)
The “half signal” for setting the soft clipper. The value set here is the input signal that will become 0.5 as an output signal. Setting this to 0.0 turns the soft clipping off. Setting this to 0.5 is maybe the closest approximation to linear while on, but is not linear. Setting this to 1.0 will match the derivative/slope of the output at zero input (so if you want the lowest forces to feel similar, and compress everything else). Therefore, less than 1.0 will amplify some lower force, and reduce larger forces. Greater than 1.0 will reduce all forces.

SoftClipUnity (Soft Clipping (Full Output)
Straight soft clipping will never reach full 1.0 magnitude, which means for lots of soft clipping scenarios, the full force of the wheel is never quite used, possibly to a noticeable level.
SoftClipUnity sets the expected maximum force that will hit the soft clipper, and rescales such that that force outputs at 1.0 (full force of wheel). This means saturation may be reintroduced if this is set too low, but it is useful to fine tune output, especially when the soft clipper is used more for non­linear response than for anti­saturation. Setting this to 0.0 turns the unity re­scaling off.


Scoop
FORCE FEEDBACK CALIBRATION

This is a new component for Topology 3, and is directly in response to some devices going flat in response at higher force levels. This is somewhat the opposite non­linear tool as the soft clipper, but is shaped differently, to better fit the nature of devices (and be easier to control).
So what scoop does is reduce lower forces more and high forces less, thereby increasing the slope of force where some devices reduce the slope of force. Since devices seem to do this in two more or less linear regimes, with a knee in between, this is how this component works (in the opposite direction so as to counter the wheel).

ScoopKnee (Scoop Knee)
The input force level where the knee is at. If this is 0.0, this component is turned off.

ScoopReduction (Scoop Reduction)
The input force reduction below the knee. Above the knee, the force slope is increased such that at 1.0 input force, the output force is 1.0.


Tighten Center
FORCE FEEDBACK CALIBRATION

Note that the tweaker name of this can be confusing. This has nothing to do with tightening the wheel about geometric top center. The “center” for this component means “zero force”, and has nothing to do with wheel position.
The primary purpose of this is to remove wheel deadzones, but it can also be a shaping tool.

TightenCenterRange (Deadzone Removal Range)
This is the input force below which the output force is increased to remove a deadzone. Put more simply, this is the size of the deadzone you are trying to remove.

TightenCenterFalloff (Deadzone Removal Falloff)
This controls how softly (higher values are softer) the output force approaches zero force as the input force goes below TightenCenterRange.


Damping
FORCE FEEDBACK CALIBRATION

One use of damping can be to counter inherent drag in a device by using negative BaseDrag. However, often devices do not have linear inherent drag, so setting BaseDrag such that there is little to no device resistance at slow wheel speed will result in accelerating forces at higher wheel speeds. This can be fixed by also having some positive BaseDragSqr.

A technique to set damping to cancel most device drag is to turn off ALL forces (F1 menu, Slow Speed Force, and TireForce) and adjust BaseDrag and BaseDragSqr such that the wheel stays the same speed or slows down ever so slightly (until it hits a stop) when you give it a good push at different rates. It seems better to have a tiny bit of drag left than to have the wheel accelerate on its own at any speed.

BaseDrag (Per Wheel Movement)
This is resistance on the wheel as a function of wheel angular velocity.

BaseDragSqr (Per Wheel Movement Squared)
This is resistance on the wheel as a function of wheel angular velocity squared.

BaseDragLoPass (Wheel Position Smoothing)
This is smoothing of the angular velocity for drag calculations. Raw position data on some devices can be noisy. Note that increasing smoothing can have a secondary apparent effect of increasing the effect of drag.

So there you have it ! (Yawn)  lol!

By the way this following link gives you a setting for every car . .66% SoP is the best one


http://pcars.oscarolim.pt/cars


Last edited by Lee Woodman on Wed Feb 22, 2017 6:32 pm; edited 1 time in total

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Re: All you need to know regarding FFB (If you have time) haha!

Post by DSRL aidtheace on Wed Feb 22, 2017 4:32 pm

Nice article mate. Definitely helpful. I will have a few more tweaks I think Very Happy
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Re: All you need to know regarding FFB (If you have time) haha!

Post by Guest on Wed Feb 22, 2017 4:36 pm

Yeah it got me looking too ! study

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Re: All you need to know regarding FFB (If you have time) haha!

Post by Hammerpgh on Wed Feb 22, 2017 8:31 pm

All good. SMS really could have benefited everyone with some better documentation regarding the FFB. Its all been left to users to provide this sort of thing.
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Re: All you need to know regarding FFB (If you have time) haha!

Post by Guest on Thu Feb 23, 2017 12:38 am

Yes, Very true. By the time this is all worked through Project Cars 2 will be out and most probably with different tolerances ! lol

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Re: All you need to know regarding FFB (If you have time) haha!

Post by stevielow on Thu Feb 23, 2017 5:47 pm

all good, there is a great vid on my youtube site done by frooglesim that explains it and more.

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Re: All you need to know regarding FFB (If you have time) haha!

Post by DSRL Webbers88 on Thu Feb 23, 2017 6:14 pm

stevielow wrote:all good, there is a great vid on my youtube site done by frooglesim that explains it and more.

stevielow

It is very handy indeed. Gives a really good insight into how to get the most out the game with you wheel. Here is the vid:



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Re: All you need to know regarding FFB (If you have time) haha!

Post by Guest on Thu Feb 23, 2017 6:35 pm

Nice one mate!

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Re: All you need to know regarding FFB (If you have time) haha!

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