rFactor2-like Grip Expression - GTR2 can do that

Shovas

Premium
For a long time now, I've been wondering why grip in rFactor 2 feels more natural than any other sim I've tried (iR, AC, ACC, AMS, etc.), and I think I've got it, and GTR2 can approximate it by tuning just one of its parameters.

but-why2.jpg


Those other sims have very good ffb but rFactor2 is doing something different in the way it expresses grip. I use the word "expresses" specifically because I'm not saying the others have wrong grip levels - only that rF2 has a different feel to grip loading and unloading. It "expresses" grip differently than most sims. It's like a more realistic feeling of rubber catching and losing the surface.

In particular, rF2 feels like it applies greater FFB weight emphasis on higher levels of steering/grip loads. So, on a straight, rF2 FFB can actually feel a little bit loose in the center but in the corners the ffb loads-up as steering forces ramp up and come on strong, not linearly. This seems right to me not only for steering and grip loads but simply for steering rack feel. Most ranges of steering are relatively easy and it's at the extremes when the weight becomes greater.

So, here it is, open up your GTR2 UserData\User.PLR file (I have attached mine at the bottom) and play with this parameter:

FFB steer force exponent="1.27500" // Steering force output "sensitivity". Range 0.0 to infinity. 0.0 to 1.0 = higher sensitivity, greater than 1.0 = lower sensitivity.

I can't find the default value but I think it was in the 0.75-1.0 range.

You should feel ffb wheel weight increasing much later into steering/grip load scenarios like cornering. This, to me, has the mental effect and benefit of helping me feel the rubber catching grip and knowing your grip levels can give you more confidence to go faster.

These other parameters are not required but may be helpful to change to feel what I feel:

FFB steer force average weight="1.00000" // How much weight is given to new steering force calculations each frame (0.01 - 1.0). Lower values will smooth out the steering force, but will also add latency.
FFB steer force exponent="1.27500" // Steering force output "sensitivity". Range 0.0 to infinity. 0.0 to 1.0 = higher sensitivity, greater than 1.0 = lower sensitivity.
FFB steer force input max="11500.00000" // Recommended: 11500 (-11500 if controller pulls in the wrong direction).
FFB steer force output max="1.00000" // Maximum force output of steering force, recommendation 0.8 to 2.0
FFB steer force grip weight="0.10474" // Range 0.0 to 1.0, recommended: 0.4 to 0.9. How much weight is given to tire grip when calculating steering force.
FFB steer force grip factor="1.00000" // Range 0.0 to 1.0, recommended: 0.2 to 0.6. How much of a factor the front wheel grip is on the steering weight.
FFB steer update thresh="0.00000" // Amount of change required to update steer force/vibe (0.0 - 1.0). Lower values = steering force updated more frequently = lower frame rate.


I'd love to hear your thoughts if you give it a try!

Note: I use an AF1 DD wheel so my parameters may be much too subtle for non-DD wheels to feel. Also, non-DD users might have an even greater deadzone around center than is acceptable. In this case, you'll have to reduce Force Exponent which may make this whole exercise moot, but what can you do. Try to keep it as >= 1.0 as possible but go lower if your deadzone is a problem. Before this I was using ~0.75.

PS. This really hit home for me in rF2 while running Flat 6 cars at Mosport. The ffb on those is fantastic.

PPS. I'm fully aware rF2 is far ahead on physics, tire model, and ffb implementation, and that accounts for why it feels so much better to me than other sims. That said, in one aspect, GTR2 can approximate something like rFactor2 grip expression, and I find that cool.
 

Attachments

  • Shovas_PLR.txt
    49.8 KB · Views: 137
Last edited:
Pretty sure that will not work on an entry-mid level wheel!
FFB steer force exponent="1.27500" // Steering force output "sensitivity". Range 0.0 to infinity. 0.0 to 1.0 = higher sensitivity, greater than 1.0 = lower sensitivity.
You want to keep that much lower. Like 0.4 - 05 or you get a huge dead zone in the center.

FFB steer force grip weight="0.10474" // Range 0.0 to 1.0, recommended: 0.4 to 0.9. How much weight is given to tire grip when calculating steering force.

You basically remove the tires from the FFB calculation . at least on low level wheels.

FFB steer force grip factor="1.00000" // Range 0.0 to 1.0, recommended: 0.2 to 0.6. How much of a factor the front wheel grip is on the steering weight.
And the little tire grip FFB you have in the calculation are exclusive calculated from the front tires! Leaving no tire grip info from the rear tires and steering gear friction!

Think there are no settings that will fit all as some settings depend on FPS for update rate and others like the pre-caned effects from "Effects Level 0-5" while others despise that.
As I always uses dgVodoo dx9>dx11 .dll mine are likely not good for even other G27 wheels as I also run high FPS.
You can try Custom level on the Effects level= it is not bad for P&G and GTL cars.
You have to do it by editing the.PLR file as you can't select the options from the Menu.

Not even sure if that Effects level= Custom do apart from more rumble effects?
 
@Bjarne Hansen, does rF2 feel good for you? If it does, it might be worth it for you to try some experiments to see how close you can get GTR2.

Pretty sure that will not work on an entry-mid level wheel!
FFB steer force exponent="1.27500" // Steering force output "sensitivity". Range 0.0 to infinity. 0.0 to 1.0 = higher sensitivity, greater than 1.0 = lower sensitivity.
You want to keep that much lower. Like 0.4 - 05 or you get a huge dead zone in the center.

Until now I had like ~0.75 but based on my experience with rF2 I feel ready to sacrifice some strength near center for a better feeling of grip.

FFB steer force grip weight="0.10474" // Range 0.0 to 1.0, recommended: 0.4 to 0.9. How much weight is given to tire grip when calculating steering force.
You basically remove the tires from the FFB calculation . at least on low level wheels.

I suspect the DD wheel allows me to go much lower and still be able to feel grip loss. That said, it's still a percentage and that means no matter your total strength you should be able to acclimatize to that percentage force and what it indicates. I have to acclimatize myself, too, from time to time, such as when I sacrifice near-center strength for strength at higher steering forces.

I find low Grip Weight values become necessary for realistic expression of grip through fast corners. You want just a tiny amount of wheel weight lightening but surprisingly not much. The benefit with low Grip Weight values is that the wheel weight that you would expect through a fast corner is still there. You know how sometimes we say sims are like "driving on ice"? Well this helps alleviate that.

FFB steer force grip factor="1.00000" // Range 0.0 to 1.0, recommended: 0.2 to 0.6. How much of a factor the front wheel grip is on the steering weight.
And the little tire grip FFB you have in the calculation are exclusive calculated from the front tires! Leaving no tire grip info from the rear tires and steering gear friction!

I got this hint from Jul's FFB Guide, "For the moment, grip information you added is 100% front grip. You feel oversteering through mass transfer. This is what happen in real steering and can be enough for wheels with sharp FFB like G25."

To put it another way, you will feel rear-end grip loss because any shift in your backend will "turn" the wheels up front, especially when considering you are always trying to drive your line and you will be correcting for that when your backend steps out.

Think there are no settings that will fit all as some settings depend on FPS for update rate and others like the pre-caned effects from "Effects Level 0-5" while others despise that.

I used to avoid "pre-canned" effects, too, but I think what people have in mind when they say that is that they think the effect is 100% artificial when, in reality, it is at least in part based on physics, the effects in GTR2, anyway. When you have physics as part of a calculation (eg. wheel rotation speed for brake vibe) that means you have information and information can help you gauge how your car is handling on track.

You can try Custom level on the Effects level= it is not bad for P&G and GTL cars.
You have to do it by editing the.PLR file as you can't select the options from the Menu.

You really do have to tune each effect when you choose to use higher Effects Levels. For example, I found the default rumble strip strength much too ridiculously high on my wheel.

Not even sure if that Effects level= Custom do apart from more rumble effects?

Here are my notes from some time ago:

Low: Steering+Grip
Medium: Adds Friction+Damper+Rumble strips
High: Adds Brake vibration
Full: Adds Throttle vibration+Steering vibration
 

Attachments

  • FFB_GUIDE.txt
    17 KB · Views: 120
Last edited:
Yes like Rf2 FFB a lot
Custom effects level is not documented as fare as I know?
The difference we got are likely the difference between setting for a high level DD like your got and a old entry level wheel (G27) that I got.
You wheel are able to transmit a lot more nuances due to the power output if we tried that on entry level weaker wheels we would not feel them.
I still would think it would be nice to feel the grip from the rear wheels before they let go?
 

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