(DIY HC/Casual+ mode, ffb tweaks) TDU2 physics tweaks 2024-07-12

Wheel Example

Notable options are override_analog_settings, steering_sensitivity, steering_deadzone, steering_wheel_mode, steering_max_angle under the overrides section, as well as the ffb_tweaks section

TDU2 sadly do not render wheel physics using constant force effect, but with spring and damper effects, basically asking the wheel to do it instead.

You'd likely need to raise spring gain and adjust damper gain in your wheel's setting software to have better wheel feedback (eg. my g29 on linux, https://github.com/berarma/new-lg4ff driver along with https://github.com/berarma/oversteer gui allows adjusting overall, friction, damper and spring effect gains; Ghub on windows on the other hand seems to not expose any of those settings and Logitech Wheel Helper seems to have stopped working with the newest Ghub)

Additionally when ffb tweaks are enabled, front wheel slipping feedback is simulated in a best effort manner

Perhaps one day the game physics engine will be studied enough for re-implementing steering phyiscs entirely

{
	"only_modify_player_vehicle":true,
	"allow_road_cars_on_dirt": true,
	"overrides":{
		"d1":"changes gravity constant, applies once on game start",
		"gravity":-9.81,

		"d2":"overrides extra gravity values in Physics.cpr, applies on change. set to 0 to remove extra downforce when airborne",
		"min_extra_gravity":0.0,
		"max_extra_gravity":0.0,
		"extra_gravity_accel_duration":0.1,
		"extra_gravity_accel_delay":0.1,

		"d3":"beta, disabling abs and tcs, weird to do in tdu2, let me know how each item feels",
		"abs_off":true,
		"tcs_off":true,
		"hand_brake_abs_off":true,

		"d4":"override angular damping values in Physics.cpr, higher values means more resistance to rotations (both turning and rolling), applies on car spawn/change",
		"override_angular_damping":true,
		"new_angular_damping":0.0,

		"d5":"steering wheel mode like in tdu1, values overrides only applies when enabled, applies on car spawn/change",
		"steering_wheel_mode":true,
		"steering_velocity":900.0,
		"steering_max_angle":40.0,

		"d6":"analog settings (controller configuration), applies on change",
		"override_analog_settings":true,
		"d7":"strength of damper and spring effects, more than 1.0 will cause clipping",
		"ffb_strength":1.0,
		"d8":"strength of sine effects, happens during surface change, driving offroad, and redlining",
		"ffb_vibration":0.5,
		"steering_sensitivity":0.25,
		"steering_speed_factor":0.0,
		"steering_damping":0.0,
		"steering_deadzone":-0.05,
		"clutch_linearity":0.5,
		"throttle_linearity":0.5,
		"brake_linearity":0.5
	},
	"multipliers":{
		"d1":"multiply some values available in tdu2vpe during load, applies on car spawn/change",
		"suspension_length_front":2.4,
		"suspension_length_rear":2.4,
		"dampers_front":0.7,
		"dampers_rear":0.7,
		"ride_height_front":1.2,
		"ride_height_rear":1.2,
		"anti_roll_bar_front":0.0,
		"anti_roll_bar_rear":0.0,
		"anti_roll_bar_damping_front":0.5,
		"anti_roll_bar_damping_rear":0.5,
		"lift_drag_ratio":1.0,
		"down_force_velocity":1.0,
		"down_force_front":1.0,
		"down_force_rear":1.0,
		"lateral_grip_front":0.6,
		"lateral_grip_rear":0.6,
		"grip_front":0.7,
		"grip_rear":0.7,
		"brake_power":1.0
	},
	"ffb_tweaks": {
		"d1":"force feedback tweaks, applies on change",
		"enabled": true,
		"d2":"to log all effects sent to dinput8 or not",
		"log_effects": false,
		"d3":"reduce damper effect as the car go faster more than the game originally does, how it feels depends on how your wheel renders damper effect",
		"reduce_damper": false,
		"d4":"adjust spring effect begin and end force scaled on car speed, 0-10000, more than 10000 will cause clipping",
		"spring_effect_max": 10000,
		"spring_effect_min": 6500
	}
}