Steering changes

[Ruud]

From the v0.8.23 readme (out tomorrow I guess):

"Steering revised quite a bit - the controls for steering left/right now use degrees, instead of being normalized. This changed some things inside the physics engine to use rotation more directly.
The idea: set your controller's lock correctly. With cars that have a steering lock that is smaller or equal to that of the controller lock, the steering is direct (1:1). If a car has more lock defined
in its car.ini, scaling will occur on the controller's steering output (now in degrees) to let it use the full range of the car's steering wheel.
This all targeted a bit for 900 degrees where you no longer then have to tweak for a lot of cars. The controller setup screen is being worked on to visually check the lock (press F5 twice in the setup screen to show the 'Wheel' page).

Why was a car.ini's steer.linearity needed again? I see no need anymore."

It's getting along nicely, hope to finish it today, but one question remains: if I have a controller that has 'linearity' applied (not 1.0) for its steering, and the controller can output >= the angle that the car's steering wheel requires, should I also disable linearity?

Example: G27 with 900 degrees of steering. Car1 has 720 steering lock. I want a 1:1 mapping. Although the Logitech G27 can go to 900 still, the virtual car's wheel only will go to 720 (clamped to the virtual car's capability).
Car2 has 1280 degrees of steering; v0.8.23 will then scale the 900 degrees to 1280 to use the full steering range, and apply linearity (which might be useful since you now steer more in the virtual car's steering wheel than in your physical real-life wheel).

Should Car1 disable linearity? I have a hunch it should, since real cars don't really have linearity applied in their steering system, do they?

 

[Mr Whippy]

Well, as Ruud has said, friction that Racer uses runs directly in the wheel at a very high frequency, kind of like an on-board feature... vs what Racer could send back and forth to the wheel via the usual channels to try simulate this effect at much lower frequencies.

Thus it seems, the 'damper' and 'spring' are actually these internal feature sets that Racer is asking to use, and setting these features to zero actually removes the effect.

Tweaking Racers "friction" while control panel "damper" is active gives a decent feel change. Double friction, and the damping feels twice as heavy, half damper value, and then the friction feels half as much.
I'd say that is Racer controlling the wheel via the 'damper' feature...


So, Racer can't run ALL the ffb locally, it off-loads the 'friction' effect to the wheel where it can be done much better.

I do think though, that this should be set per car, or have factors per car, so we can get the mixes of weight and feel really nice. Standards will be needed though, still nothing worse than driving one car that rips your arms off, then another that is super light. Much like the FF effects on tracks, some are enough to have my house shaking when I drive on a patch of sand (read Carlswood hehe)


Yep, kpi offset is working, seems negative in metres for susp0 and positive in metres for susp1 is about right for normal road cars. Say -0.05 and 0.05 side to side. Not sure what a realistic value is for a fwd. I think you will certainly feel torque steer with this active hehe!


All good.

Dave

 

[Alex Forbin]

Ah, I see now. Thanks Dave.

Alex Forbin

 

[Ruud]

I'll make a document on steering wheels on racer.nl (hopefully tonight). These things are hard to understand really (what can be done using low-frequency signals), and it's good to have a specific 'chapter' on how to setup your steering wheel, plus how it all works.
As Dave explained, high- and low-frequency are important things to consider for friction. Funny thing is that with 'damper' in the driver, the probably ALSO mean friction.
- friction: if vel>0 frictionForce=100 else frictionForce=-100
- damping: frictionForce=vel*k

So damping is velocity-dependent, friction isn't. But you really really need friction to be turned on. I'm surprised the spring needs to be turned on, I'll make screenshots of my Logitech settings (at home, I don't have a G27 at the office) and explain on how things work and what settings should be set. Very useful for other people that don't understand it yet, and it's indeed core to Racer. Funnily enough around the same limitations apply to high-end wheels; friction is just so high-frequency...

 

[Mr Whippy]

It's made so much difference here it's amazing


Just a few points for clarification.

Friction is always the same for all cars?

ff_factor per car is ONLY adjusting Mz and kpi offset forces?

Or does ff_factor factorise the friction too?


Would be nice to factorise as per my previous post to give really nice control and consisency across cars. Eventually. Can just default to 1 for now, for users who don't get them and for old content to still work ok

Dave

 

[Ruud]

ff_factor indeed only adjusts the forces you see in the Ctrl-1 screen (Pacejka/caster/kingpin). Friction of the wheel is currently only set through the controls file, and thus quite static. I'll see if I can factorise things a bit in car.ini, and add a friction/friction_slow.

The threshold for slow friction is 20 m/s btw (72 km/h); a bit high, I'll decrease that to around 5 m/s (18 km/h), which is what we use on our platforms.

 

[Mr Whippy]

Hmmm, yeah, worth a try at 5m/s for now.

That sounds cool Ruud.

It's so funny that for years many of us with DFP or G25 have been using Racer without friction there. I'm so annoyed I've missed out for probably years!

It really does totally transform cars. I'm now using much higher ff_factors and cars just feel amazing

I drove GT5 P (F430) and GT5 TT last night at my new screen (PS3 next to PC to my monitor), and then went to Racer and the level of feedback and FF quality is just on another level in my view (using F458)
Of course, maybe it's too much feel and intensity for some boring cars hehe, but that is where these factors will be useful, so we can get a bit less life to the Mz/castor forces etc, add in a good dose of friction/damping, but still be able to crank up the overall weight a bit so it's not too light


Exciting stuff. Hehe, still can't believe it's a feature that has sat there for years and I've not been enjoying it!

 

[Ruud]

Incredible. I should really write up on FF tonight since a lot of people probably have the same issue.
Note that the F458 may have quite a bit of steering (even though with the hands animating it sure is cool); in real life at least the F430 Challenge has only around 180-200 degrees of steering lock. The regular F430 may be different though. But so the F458 may have quite a bit of lock (720 degrees now?).
Note that also influences the FF directly, as steering ratio decreases, and you need to tweak ff_factor again.

 

[QuadCoreMax]

@QuadCoreMax: As Alex said, it's best to turn off that artificial spring from the wheel driver. The wheel should just stick in any position if you stand still. I always have it turned off and the rest set to 100%.

Hm, I've tried as Alex suggested, but I can't say I love the steering feeling. Normally, when you turn the steering wheel (in real) & let go suddenly, you have a centering force which re-centers the wheel with a certain speed & linearity.

So really it is then upto the wheel too make good friction. I might add a slider in the setup screen to change it live.

Cool thing.
Stealing G27 friction (3000 & 6000) values to G25 doesn't create anything good, just a lot of rumble & shaking.

@Dave

LoL man !

KPI should now let us feel bumps in the road through the steering wheel correct?

I'm feeling bumps in the road, odd thing guys...
I think we need to create some car.ini profiles (just the physical part) + controller.ini too & do some more testing to get a better understanding.

 

[Mr Whippy]

I'm having issues with the kpi offset Quadcoremax...

If you set both values positive or negative, and brake, you can really feel it in action.

However, I'm not really feeling a tugging on split Mu surfaces (ie, one wheel on grass, the other on tarmac)... nor am I feeling it under braking much.

However, on a bumpy road (road_noise fairly rough), then I can really feel it tugging left and right more than it did!


As per the G27 friction, I'm thinking they are fine here. What max_force are you using, and windows control panel settings? I kinda went to about 2000/4000 here, with ff_factor on my M3 at about 0.7 and it felt really quite good. A good all-round blend.

It's getting that blend right that is important. Like you say, it needs to be able to self-centre with Mz and castor nicely, but then have friction to hold it there, and not have it skitting left and right down the road.


This is where those factors will be handy.

Factors to get the mix right.
Factor per car to get it's force right vs others.
Factor overall per user preference for the whole game (or turn it down at night to stop shaking the house apart )

Dave

 

[Cosmo°]

Ruud, I seem to be getting a viscous behavior from the friction - is that intentional? Standing still and turning the wheel slowly gives me very little resistance, trying to speed up the motion makes the resistance increase a lot. Same thing happens on the roll. While small corrections to a slide are not significantly affected, catching the car after a big, sudden grip loss (like dropping a wheel onto the grass on turn in) is made artificially difficult because of this increased resistance. It also means that the sensation of having a weighty steering system is not consistent.

 

[Ruud]

Ruud, I seem to be getting a viscous behavior from the friction - is that intentional? Standing still and turning the wheel slowly gives me very little resistance, trying to speed up the motion makes the resistance increase a lot. Same thing happens on the roll. While small corrections to a slide are not significantly affected, catching the car after a big, sudden grip loss (like dropping a wheel onto the grass on turn in) is made artificially difficult because of this increased resistance. It also means that the sensation of having a weighty steering system is not consistent.

I find my G27 only seems to do best when it's already generating a force; it then modifies the force a bit. When standing still, it seems to cut all forces, so slowly moving kills the friction/damping/inertia effects. I guess that's also to do with the fact that it is a 'consumer' wheel; even on high-end gear, we are careful with friction & damping, esp damping can make a wheel unstable.

v0.8.24 has sliders for friction/stick_friction/damping (velocity relative) and inertia (acceleration relative).

 

[Mr Whippy]

This is going to be fun to tinker with

Any chance of the syntax for console editing these values, console reloads/edits make things so much more intuitive to tweak... if possible of course!

Thanks

Dave

 

[Alex Forbin]

Incredible. I should really write up on FF tonight since a lot of people probably have the same issue.
Note that the F458 may have quite a bit of steering (even though with the hands animating it sure is cool); in real life at least the F430 Challenge has only around 180-200 degrees of steering lock. The regular F430 may be different though. But so the F458 may have quite a bit of lock (720 degrees now?).
Note that also influences the FF directly, as steering ratio decreases, and you need to tweak ff_factor again.

Any chance of getting the F458?

Alex Forbin

 

[Mr Whippy]

Hi Alex,

The F458 is a wip by Camsinny... I keep pestering him to get it something a bit more finished so it can be released but right now it's a full on mess. I've only had it because I've been working on the car.ini, and I think Ruud and Mitch for making the hands do the steering wheel and flappy paddles (albeit still with some bugs)

Rest assured, I'll keep nagging at Cam to get it finished asap for us all to enjoy... and as a fantastic example of most (if not all) of Racers features currently well implemented in a car.

Dave

 

[QuadCoreMax]

v0.8.24 has sliders for friction/stick_friction/damping (velocity relative) and inertia (acceleration relative).

Thx for all efforts, we really appreciate it !

@Dave

I can understand, having same probs, will also try to fix my F430 GTC visually + physically.

 

[Ruud]

That document about steering wheels & such is up at http://racer.nl/tutorial/forcefeedback.htm
The F458 is easy to oversteer, the Mz curve seems to give up too quickly compared to Fy. Hope Cam will finish it for v0.9, the animated steering is very nice although I should create the tutorial to see where the animation problems are coming from (perhaps the bone animations are not correct, steering & shifting at the same time is troublesome). Also, it'd be nice if a 900 degree animation could also be used for a 200 degree (steering lock) car, to save precious animation time.

 

[QuadCoreMax]

In Shift, it looks like this, maybe it'll give some new ideas...

<_cForceSettings Level="Full" Gain="1.000000">
        <Flags ThrottleFxOnSteerAxis="1" BrakeFxOnSteerAxis="1" RumbleForce="0" />
        <_cSteering FrequencyMultiplier="0.000000" ZeroMagnitude="0.035000" Slope="0.000000" WaveType="Sine" AverageWeight="0.600000" Exponent="0.990000" InputMax="11500.000000" OutputMax="1.700000" GripWeight="0.800000" GripFactor="0.600000" UpdateThreshold="0.000150" FrictionCoefficient="0.175000" FrictionSaturation="1.000000" DamperCoefficient="0.175000" DamperSaturation="1.000000" />
        <_cThrottle FrequencyMultiplier="0.400000" ZeroMagnitude="0.020000" Slope="0.000000" WaveType="Sine" UpdateThreshold="0.020000" />
        <_cBrake FrequencyMultiplier="0.900000" ZeroMagnitude="0.020000" Slope="0.000000" WaveType="Sine" UpdateThreshold="0.020000" />
        <_cRumbleStrip Magnitude="0.250000" FrequencyMultiplier="0.500000" WaveType="Sine" PullFactor="-0.700000" UpdateThreshold="0.075000" />
        <_cJolt Magnitude="1.300000" />
        <_cSpring Saturation="1.000000" Coefficient="0.000000" />
        <_cGearChange Magnitude="0.250000" FrequencyMultiplier="1.000000" WaveType="Square" />
        <_cWheelSpin MinWheelSpin="0.000000" MinMagnitude="0.000000" MaxWheelSpin="0.000000" MaxMagnitude="0.000000" FrequencyMultiplier="1.000000" WaveType="Sine" />
    </_cForceSettings>
    <_cControllerSettings SpeedSensitiveSteering="0.600000" DampeningTimeCentreToLock="0.500000" DampeningTimeLockToCentre="0.300000" DampeningTimeOppositeLockToCentre="0.300000" DigitalRampRateSteering="0.200000" DigitalRampRateThrottle="0.500000" DigitalRampRateBrake="0.500000" DigitalRampRateClutch="0.200000" NominalRiseDamping="0.950000" NominalFallDamping="0.750000" MaxSteerVelocity="3.141593" NominalYawAngle="0.785398" TurnDeadzone="0.000000" ThrottleDeadzone="0.050000" BrakeDeadzone="0.050000" ClutchDeadzone="0.050000" TurnSensitivity="0.500000" ThrottleSensitivity="0.500000" BrakeSensitivity="0.500000" ClutchSensitivity="0.500000" WheelLock="1.000000" WheelLockDegrees="270" AlternateWheelLock="1.000000" AlternateWheelLockDegrees="270" AlternateSpeedSensitiveSteering="0.000000" />

Cool tutorial

 

[Mr Whippy]

The F458 is easy to oversteer, the Mz curve seems to give up too quickly compared to Fy.

Hmm, not sure which ini you have, I think the Mz's were reset after our discussion about those... which made it more nice feeling.

It still oversteers though, 560bhp for you

Dave

 

[camsinny]

Yeah I'm re-doing the driver today actually. The lod0 and lod1 are giving me headaches ATM so trying to do something else. Plus the driver looks horrible ATM.
There's not THAT much still to do so it should be ready for 0.9
...Hopefully.

 

[Alex Forbin]

Hi Alex,

The F458 is a wip by Camsinny... I keep pestering him to get it something a bit more finished so it can be released but right now it's a full on mess. I've only had it because I've been working on the car.ini, and I think Ruud and Mitch for making the hands do the steering wheel and flappy paddles (albeit still with some bugs)

Rest assured, I'll keep nagging at Cam to get it finished asap for us all to enjoy... and as a fantastic example of most (if not all) of Racers features currently well implemented in a car.

Dave

It sounds like a good default car since it will have all the latest features.

Alex Forbin