1.2

This mod modifies the default grip model used by the resizable wheel, hereby referred to as the "rectangular" grip model, with an "elliptical" grip model based on simcade games to better resemble real tires.

The unique handling styles of each drivetrain type come from the "circle of forces" - as longitudinal slip approaches the limit, lateral grip is reduced. Differences in traction between the front and rear wheels will produce different behaviors on different cars. However, the vanilla rectangular grip model does not have have this relationship between lateral and longitudinal grip, and therefore, most special features of each drivetrain type are lost.

The mod aims to restore those effects by setting grip multipliers in the direction perpendicular to grip demand. The slip extremum and asymptote values are used to create one ellipse each for slip extremum and asymptote. If the slip remains within the extremum ellipse, the wheel is considered to be under normal loads and there is no grip reduction along either axis. However, as the wheel exceeds the extremum ellipse and approaches the asymptote ellipse, it is considered to be overloaded, and grip is reduced in the direction perpendicular to slip.

In addition, tire smoke and skid marks are added based on how much the tire is overloaded.

The following Desmos graphs are used for prototyping. Some equations are provided but may differ from those used in the mod.
[1]
[2]

OTHER

The following mods are used in thumbnails:

• Jundroo-City by FlyingPatriot
• Nordschleife by FlyingPatriot

NOTICE

• Tested in 1.12.203.0.
• Satisfactory results can only be obtained if a car is reasonably realistic and tuned for this mod.
• The mod has no effect if none of the wheels has a slip that exceeds the extremum zone, i.e., the handling must be limited by grip.
• The mod has no effect on landing gear parts that are not using resizable wheels.
• The script checks for new resizable wheels every 10 seconds. It will take a moment for newly spawned AI aircraft to be affected.
• Particles use the existing particle system on wheels, which in the vanilla game, only activated during a hard landing.
• Skid marks may not support irregular combinations of rotation and scale of resizable wheels.
• Settings data is saved under NACHSAVE\EGS.DAT. The file is created after restarting or quitting a level for the first time. Settings can be reset to default by deleting this file.
• Does not use real-life physics data.

CONSOLE COMMANDS

EllipseGrip_ToggleDebugMode
Displays grip multipliers and wheel slip for all resizable wheels in the scene.

EllipseGrip_ToggleParticles
Turn on or off the emission of particles. Previously emitted particles are not removed.

EllipseGrip_ToggleSkidmarks
Turn on or off skid mark generation. Previously generated marks are not removed.

EllipseGrip_SetParticleAlphaExponent
The wheel overloading factor is raised to this exponent to get the opacity of particles. Increasing this will reduce smoke density at low overloading factors. Default: 3

EllipseGrip_SetParticleColor (color c)
Set a tire smoke color. Default: 1,1,1,1

EllipseGrip_SetStrength (float strength)
Set the maximum loss of traction perpendicular to slip. Default: 0.25

EXAMPLE CARS

Notice: Example cars are tuned for the mod. They will drive differently (maybe badly) without the mod.

MRC FLEX-V EGS
RWD car with rubber more suitable for erasers than sports cars. In MT mode, gear 4 and above will largely prevent any wheelspin.
You can also try the extremely simple traction control by activating it in the variable setters menu. (It just cuts power when wheelspin exceeds the extremum value)
Like the original car, you can use AG3 for linear steering mode. With a steering wheel and a lot of skill, it should be possible to recover from spins. It is largely impossible to recover from spins in steering assist mode as the steering angles are too small.

MRC FLEX-V EGS-2
Added a simple limited-slip differential that outputs a correction torque proportional to the angular velocity difference of the rear wheels. It prevents the free-spin of a single rear wheel, which can happen due to bumps or cornering.
In addition, a counter-steering assist factor has been added to the steering assist mode, but its performance is poor.

MRC FLEX-V EGS-2a (Assist Prototype)
Added TCS on Activate4. If there is excessive longitudinal slip in the direction of motion, the engine input will oppose it. Sensitivity is proportional to gear ratio.
Added ABS on Activate5. If there is excessive longitudinal slip against the direction of motion, the engine input will oppose it. (This does not mean that the brake torque can be set high! You should still use a brake torque close to or less than the amount required to lock the wheels.)
Changed grip curve so it falls off more gently after the extremum point.
There is a bug that affects edge cases of throttle and brake combinations. This will cause the car to stop before continuing.

NIKE ONE 2022 EGS
Second re-tune of the funny car. It is possible to change the drivetrain without touching any FT, but two tires cannot handle the power.

VERSION HISTORY

1.2 (2312272020)

• The settings that can be changed using commands are now saved when exiting or restarting levels.

1.1 (2310142330)

• Added skid mark visual effect using UnitySkidmarks by Nition
• Added tire smoke exponent to reduce smoke density at low tire overload levels
• Fixed incorrect behavior of SetParticleColor command

1.0 (2309232130)

• Initial release

KNOWN ISSUES

• When a tire leaves the ground, smoke continues to be emitted. Unfortunately, the IsGrounded property of resizable wheels does not work as expected, so I cannot use it for this purpose.