Rear Wheel Drive[The LackofGrip] Workaround Tutorial

Discussion in 'Automation' started by G-Farce, Jan 18, 2020.

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  1. G-Farce

    G-Farce
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    As is currently:
    • Parts 1-3:
      • Part 1 is mandatory reading.
      • Parts 2 & 3 focus on better realism, going hand in hand.
    • Wheelie Tutorial
    More if interest is peaked. Unfolds and evolves as it comes to me. WIP
    PART 1, Intro:
    I'm quite frankly sick of seeing front-wheel biased AWD in cars that can clearly and should be clearly Rear wheel drive. So here's a great and easy method to work around the insane lack of rear grip that automation can spit out from the exporter. This method also allows you to use ANY type of tyre and ANY tyre width, so you no longer have to pretend that your cars come with good, slim tyres from the factory!! This also opens up the options for your creativity tenfold. So I hope you find it useful as I did, let me know and if there are mistakes! However you will still need to have worked on the suspension and differential to appropriate values before you correct this. Moving forward:

    Steps 1-3:
    1) Open your zip file,
    2) find wheels_rear.jbeam,
    3) edit it, save and copy it back to the archive to overwrite original
    Additionally, if you can do all this with the car open in game somehow, then let me know!

    Expanding:
    2) Skip to the bottom of the file you'll find these:

    //advanced friction values
    {"noLoadCoef":1.826805}, //The friction coefficient with no normal force on the tire (highest possible coef)
    {"loadSensitivitySlope":0.000157}, //Determines the rate that friction coef drops off as normal force is added. Acts per node, in coef/Newton of normal force
    {"fullLoadCoef":0.724923}, //Minimum friction coef. Adding more normal force will not decrease the friction any more than this
    {"softnessCoef":1.000000}, //Influences the time variant friction behavior. Max value of 1 makes the tire more like soft racing slick rubber

    Do this:
    Increase noLoadCoef to anywhere below 1.97. Usually 1.866 will do.
    Note: This is a critical value. If your noLoadCoef is 1.43xxxx for example, we change it up by 0.03-0.06 to start because too much could cause massive understeer, from lack of front tyre grip balance. We would change it to 1.47 and test it. Should be noticeable difference. More if not enough.Testing and tuning is the game here. You may need to come back to this value later and reduce it closer to the original value if you're not happy with the understeer from the front.

    Decrease loadSensitivitySlope to a minimum of 0.000050 if desired, improves car handling overall by slowing down grip loss at the tyres.
    Increase fullLoadCoef to any value. The higher, the more friction you will have when you are out of control of the car, but this will also make it that you struggle to do burnouts if too high so keep it under 0.95. Recommended value: 0.861230


    I do hope to see more rear wheel drive cars in future, and if they're under 300hp that's cool too!
    If anyone knows how to increase steering lock, that's something I need to know, shoot me a pm.
    Seems like the values are similar to Assetto Corsa in some regards. 0.95 is a common tyre value for standing friction..?

    I like how some cars feel like GTA5 style handling when you take some values a bit far. It's fun to drive a car that feels like you would in that game, it's just easy and carefree to drive but paired with great content and crash physics of BeamNG!

    It's more realistic to tweak things yourself than to rely on automation exporter to do everything correctly as it's simply a standardized tool that not only gets things flat out wrong as other users report but it also doesn't work for special uses. Like how we can't make modern F1 engines because the rev limiter is 12k instead of 19.
    0) GTAV?? car: 58FR 400hp 1300kg Semi slicks, sedan 2.7m
    Rear:
    {"noLoadCoef":1.976805}
    {"loadSensitivitySlope":0.000057}
    {"fullLoadCoef":0.924923}
    {"softnessCoef":1.300000}

    1)

    Another tip is to set the car you're using/editing as default then the game loads your car , click "overwrite default" at the top of car selection menu to do this.
    Happy modding mates!
     
    #1 G-Farce, Jan 18, 2020
    Last edited: Feb 21, 2020
  2. G-Farce

    G-Farce
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    PART 2:
    This is where we get into the meat of it, if you're looking for more meaningful corrections, this will do the trick for front and rear. This is taken from my corrected example car. Highlighted in Bold are the values that need increasing/tweaking, where underlined is to be decreased as desired :

    One thing to note is I was able to turn my rwd terribly snap-oversteer stockcar into a car that behaves very much like it's awd with a tendency to understeer out after using quick values for front and rear.

    //tire options
    //sidebeams need to be high in expansion to control rolling resistance and tire expansion, but low in compression to allow air pressure to hold the weight
    {"wheelSideBeamSpringExpansion":392380.437500,"wheelSideBeamDampExpansion":25.659901},
    {"wheelSideBeamSpring":0.000000,"wheelSideBeamDamp":12.829950},
    {"wheelSideTransitionZone":0.100000,"wheelSideBeamPrecompression":0.980000},

    //tread beams mainly control lateral stiffness of the tire, the higher the more responsive the handling
    {"wheelTreadBeamSpring":214108.031250,"wheelTreadBeamDamp":34.437538},
    {"wheelTreadBeamPrecompression":0.990000},
    {"wheelTreadBeamDampCutoffHz":500.000000},

    {"wheelTreadReinfBeamSpring":125643.218750,"wheelTreadReinfBeamDamp":21.780210},
    {"wheelTreadReinfBeamPrecompression":0.990000},
    {"wheelTreadReinfBeamDampCutoffHz":500.000000},

    //periphery beams mainly control longitudinal stiffness of the tire, the higher the values, the higher the peak grip, but can have more abrupt loss of traction
    {"wheelPeripheryBeamSpring":161675.031250,"wheelPeripheryBeamDamp":19.286777},
    {"wheelPeripheryBeamPrecompression":0.990000},
    {"wheelPeripheryBeamDampCutoffHz":500.000000},

    {"wheelPeripheryReinfBeamSpring":110837.515625,"wheelPeripheryReinfBeamDamp":13.637812},
    {"wheelPeripheryReinfBeamPrecompression":0.990000},
    {"wheelPeripheryReinfBeamDampCutoffHz":500.000000},

    //adds lateral stiffness to the tire structure, replicating stiff sidewalls
    {"wheelReinfBeamSpring":11780.410156,"wheelReinfBeamDamp":159.192963},
    {"wheelReinfBeamPrecompression":0.990000},
    {"wheelReinfBeamDampCutoffHz":500.000000},


    //general tire values
    {"nodeWeight":0.167804},
    {"nodeMaterial":"|NM_RUBBER"}, //Material just changes sound, skid marks, particles
    {"pressurePSI":"$rearPSI"}, //Tire pressure
    {"dragCoef":5}, //Air drag

    //groundmodel friction multipliers
    {"frictionCoef":1}, //Multiplies the groundmodels maximum friction coefficient
    {"slidingFrictionCoef":1.4}, //Multiplies the groundmodels minimum friction coefficient
    {"treadCoef":0.000000}, //How much grip loss on rough groundmodels. Max value of 1 for the best off road tires

    You saw there are only 4 values here to alter amongst a wall of text. These are also fairly straightforward, for front tyres may be different strategy, it's upto you whether to increase or decrease.


    Tips/notes: slidingFrictionCoef should not be higher than 1.7 on rear tyres, to avoid causing artifical wheelie effect. keep it from 1 to 1.2 maximum best values I've found are around 1.16, handle with care
     
    #2 G-Farce, Jan 20, 2020
    Last edited: Jan 20, 2020
  3. RobertGracie

    RobertGracie
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    Thanks for pointing a bug like this out, at least I know there are people out there working on correcting minor errors and stuff like this :)
     
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  4. G-Farce

    G-Farce
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    PART3: This is only for those chasing more realism in their car behavior, and so far the best template to follow: This is from a fresh start, so for cars that haven't been "fixed" using the above, their values are untouched and need to be at their exported value, then you continue:

    Problem: Sporty Car with natural tendency to oversteer, oversteers near uncontrollably upon full throttle with a locked differential:
    Template 1 fix for wheels_rear.jbeam:

    {"noLoadCoef" Increase by 0.01-0.02, no more. ex.if 1.575xx increase to 1.585xx and no more. Because too much generates overkill understeer at the front.

    {"loadSensitivitySlope":0.000157}, if over 0.000100 decrease to 0.000055
    //Determines the rate that friction coef drops off as normal force is added. Acts per node, in coef/Newton of normal force

    {"fullLoadCoef":0.724923}, If under 0.60, increase to 0.80
    //Minimum friction coef. Adding more normal force will not decrease the friction any more than this

    {"softnessCoef":1.000000}, If under 0.7, decrease to 0.2
    //Influences the time variant friction behavior. Max value of 1 makes the tire more like soft racing slick rubber

    Scroll up to part 2 values, from bottom to top this time, using existing values for example scaling:

    {"slidingFrictionCoef":1.0}, increase to under 1.2, possible values: 1.06, 1.12. 1.14 etc. This value should not be increased past 1.2, period.
    //Multiplies the groundmodels minimum friction coefficient
    {"wheelReinfBeamSpring":12780.410156 decrease by 1-2k
    {"wheelPeripheryBeamSpring":201675.031250 decrease by 4k
    {"wheelTreadBeamSpring":214108.031250 decrease by 4-6k ex. 164108.0



    When you are happy with the rear end oversteer, and if it's time to address that front end push 'understeer':
    the quick n dirty fix is slidingFrictionCoef 1.03 and no more to wheels_front.jbeam, this will make it more twitchy and far more sensitive on the straights and long roads. but you will solve the understeer problem entirely and bring out the characteristics of the car. Though in general it is advised against this fix for the front wheels if you have the time to spare. Keep it at 1.0 normally and decrease front lateral tyre spring rates instead.

    Some new values to play around with for wheels_front.jbeam see this section:
    {"enableTireReinfBeams":false},
    {"enableTireLbeams":true},
    {"enableTireSideReinfBeams":false},
    {"enableTreadReinfBeams":true},
    {"enableTirePeripheryReinfBeams":true},
    On lower powered cars especially, you can gain some "simulation value" by changing "false" to "true" in both values, I've noticed that this lets my tyres clip through the ground organically, but exaggerated, as if it is turning visual tyre deformation fully on. Perhaps the beamspring values we reduced earlier are taking its toll here. Not much is known but super fun to play with, seems to give me better tyre feel and overall motion but I suspect it will break your car with more powerful machines.

    Edit: Experiemental Methods Update Feb 6th 7am:
    Problem: Mclaren snap oversteer due to disconnected feeling with the car with minimal steering, now catching the controlled snap oversteer, it instantly snaps harder in the other direction upon catching it, as if the car suddenly has no swaybars installed.

    Solution example: Front tyre file:


    //periphery beams mainly control longitudinal stiffness of the tire, the higher the values, the higher the peak grip, but can have more abrupt loss of traction
    {"wheelPeripheryBeamSpring":191544.687500,"wheelPeripheryBeamDamp":17.956434},

    Above, This previous values I used on the mclaren 650s were wrong for me for this edit, and the rear tyre was in the low 20s, The problem for me was the rear would snap harder into opposite oversteer after I countersteered the first snap. My solution, idea was to increase front end stiffness in such a layered way that the rear is always being tested 'primed' by the front behaviour, so that when the car unloads it's not such a big shock to the balance, I simply made the Damp a little less than it's supposed to be while bumping both up to this(more in line with the rear tyre values):

    //periphery beams mainly control longitudinal stiffness of the tire, the higher the values, the higher the peak grip, but can have more abrupt loss of traction
    {"wheelPeripheryBeamSpring":231544.687500,"wheelPeripheryBeamDamp":20.956434},

    Now the car handles so much more realistically across the board while improved control, it's amazing how simple changes can make the difference. Like the missing puzzle piece.
     
    #4 G-Farce, Jan 24, 2020
    Last edited: Feb 5, 2020
  5. Kevin97

    Kevin97
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    Hi, we appreciated your work. It certainly reduces the time during the production of a model.
     
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  6. G-Farce

    G-Farce
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    Fantastic. This is great to know others are finding it useful. Hopefully more people are willing to try things outside the box and in future!
     
  7. l5o2k1s

    l5o2k1s
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    Great tutorial! I tried modifying the groundmodel friction coef (like the supper grippy tires mod for regular beam cars) but like that mod - the results where far from realistic.
    Can't wait to try your technique out!

    If you want to be able to change the values in the jbeams while the game is open just unpack your mod - that way you only need to refresh the model for the changes to take effect, and you dont get the archive is being used by another program bs. You can refresh it either by loading it in again or by changing any part on it(it bugs out if you want to add more parts/variants on the fly)

    Also, you can use variables for the values you want to change, and they show up in beam. Just add to the variables already in "wheels" - the Tire Pressure ones

    e.g.

    "variables": [
    ["name", "type", "unit", "category", "default", "min", "max", "title", "description"]
    ["$rearPSI", "range", "PSI", "Tyres", 30, 5, 45, "Rear Tyre Pressure", "Initial Tyre Pressure", {"stepDis":0.5}]
    ["$noLoadCoef", "range", "coef", "Tires", 1.5, 1, 2, "Rear tire onloadcoef", "whatever"{"stepDis":0.001}]
    ["$fullLoadCoef", "range", "coef", "Tires", 0.9, 0, 2, "Rear tire fullloadcoef", "whatever"{"stepDis":0.001}]
    ],


    Here it's just for the no load and full load coef - for "loadSensitivitySlope" - just change the name & title and the values. the first number's the default value, then min & max (it confused me a bit at first). {"stepDis"... is optional.
    Then add the variable to the value you want to control:
    //advanced friction values
    {"noLoadCoef":"$noLoadCoef"}, //The friction coefficient with no normal force on the tire (highest possible coef)
    {"loadSensitivitySlope":0.000066}, //Determines the rate that friction coef drops off as normal force is added. Acts per node, in coef/Newton of normal force
    {"fullLoadCoef":"$fullLoadCoef"}, //Minimum friction coef. Adding more normal force will not decrease the friction any more than this
    {"softnessCoef":0.600000}, //Influences the time variant friction behavior. Max value of 1 makes the tire more like soft racing slick rubber

    Find new names for the front - i just found out.

     
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  8. G-Farce

    G-Farce
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    Wow, this stuff this is all pretty neat I will have to try it out. I'm Speechless. Anywho, hope the tutorial also helps you get some results, and if you find better values etc to use if you do go that far with it. Need to figure out how to unpack my mod first. I remember reading about it on the old wiki!
     
  9. l5o2k1s

    l5o2k1s
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    You can unpack it from beam, goto mods > mods(tab) select ur mod and unpack, or with winrar or 7z unpack to "ur_named" folder - and move it to the unpacked folder(inside the mods folder)
     
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  10. G-Farce

    G-Farce
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    WHEELIE(DRAG TYRE) TUTORIAL

    Little update. Something a little different, a
    Wheelie tutorial: This is just for fun, and it's very easy to do. Learn how and you'll barely need 5 minutes to make any RWD wheelie, whenever you like.

    Alright for this template, quick and dirty, you can increase these 4 a bit. Keep in mind this is for a wheelie car primarily without any burnouts before launch, involving burnouts and more in-depth thermodynamics into the equation, to generate temperature-dependant wheelies, is completely out of the scope for this tutorial, and my hands. Anyone knows more about it, let me know. Moving forward:

    {"wheelPeripheryBeamSpring":308044.625000,"wheelPeripheryBeamDamp":25.991306}, by ~5 each. WPBS likes to be a little stiffer compared to the damp. Failing this can prevent wheelies from starting at all.

    {"frictionCoef":1}, //Multiplies the groundmodels maximum friction coefficient. No higher than 3.4. Usually difficult to make wheelstand cars with values under 2.4, unless every other value is exaggerated. Even with a value of 2.3 here(my car has really wide tyres), it seems unable to give you a good looking wheelie as you lay skidmarks, losing traction, still can look rather cool with the car squatting mid-launch and one wheel lifting up. 2.4 and up is usually required for anything close to a "good wheelie"

    {"slidingFrictionCoef":1}, //Multiplies the groundmodels minimum friction coefficient no higher than 2.42(but untested overall)


    {"fullLoadCoef":0.738951}, //Minimum friction coef. Adding more normal force will not decrease the friction any more than this. This one is really important, it affects the above massively if it's too low. Makes tuning harder if it's not above 0.66. Being below 0.60 often results in tyre spinning on launch (with cars over ~1000hp) and takes forever to hook up when making realisitic drag tyres and attempting for realism and not exaggerated values in the above 3 slots. Drag tyres never need this value to be below 0.6, as always check and correct your other values first.

    Your aim throughout every correction should not be to make a car that bounces up and down while wheeling! Instead your aim is to get one good wheelie from launch and the front to lower slowly after 200ft and never rise again.
     
  11. RobertGracie

    RobertGracie
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    Dude this is awesome you are doing a great job here of fixing problems!

    off topic sorry I am beginning to wonder why G-Farce isnt a staff member yet hes got the grades and skills for the job I mean hes deep into the code like no one else is and well yeah
     
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  12. G-Farce

    G-Farce
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    I'm glad it's useful to some :) I'm just adding a bit here and there, there's so many great people and on this forum that do far more than I can, but now that you mention it, hmm Staff member? I'm trying to wrap my head around it but the suggestion alone is awesome!

    Off topic is fine with me! This is here as a rough guide to help people with some aspects of automation cars
     

    Attached Files:

    • upload_2020-2-21_22-3-7.png
  13. RobertGracie

    RobertGracie
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    I know what you mean about automation cars they are well a bit low quality mods they are not as bad as the Russian mods but still some people class them as better russian mods its not right
     
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  14. G-Farce

    G-Farce
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    I don't care for the Russian vs Automation mods arguement here. Both simply exist. As for Automation, once you get over the hurdles, it's is great fun. I didn't expect nearly as much use as I got out of it still a WIP after all, but boy that sucked me right in. As for comparing Automation mods against others, that's upto the end user to decide for themselves. But I really welcome all kinds of mods. The sillier the better. The more mods the better! I was taken back by some modders, it's amazing to see people taking automation bodies, adding in full interiors and changing every aspect of it down to the tiniest detail. Especially amazed by the integration of the universal wheel system for more Automation cars. Really cool what people are doing with it, keeping it fresh.
     
  15. Kevin97

    Kevin97
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    The next model will be a small sports car, rear wheel drive with 320hp.
     
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  16. G-Farce

    G-Farce
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    Nice. That's in the ball park for me. Looking forward to it. The low-mid end sportscars category imo, are the best mod cars
     
  17. neka_budala

    neka_budala
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    Mate you are a god. Finnaly i can make my not a koeingsegg RWD. they should hire you as a staff mebem as posted before
     
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