DriverD

Release history:
 
TDU2 Physics Tweak
Nudge tdu2 overall car handling to your own liking, along with force feedback tweaks 😄
https://github.com/Kethen/tdu2_physics_tweaks
Video demo of the example config below, speedometer is in kph (Streamable)
Video demo of the adjustable steering wheel mode (Streamable), enabled by setting "steering_wheel_mode" to true
Known issues
- The plugin causes game crashes on the 21MB exe and I have yet to find out why, considering how it would only crash after roughly 3 races of driving, I believe the 21MB exe might have some sort of exe integrity check that was not fully patched out
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Installation on Windows
Place dinput8.dll, MinHook.x86.dll, tdu2_physics_tweaks_config.json, dinput8_ffb_tweaks_i686.dll and tdu2_physics_tweaks_i686.asi next to TestDrive2.exe.
Installation on Linux+WINE
Copy the file next to TestDrive2.exe following the Windows instruction.
After that you'd likely also have to declare a dll override before the asi loader as dinput8.dll will be picked up. It can be done in winecfg or with the below environment variable.
export WINEDLLOVERRIDES="dinput8=n,b" Alternatively, if you are already using dxvk, chances are you have a d3d9.dll override ready to go. Simply install dinput8.dll as d3d9.dll instead.
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Usage
After installation, edit tdu2_physics_tweaks_config.json to nudge the game closer to your taste.
Some values can be adjusted while the game is running. Check the in-json string comments for when values are applied.
The following examples adjusts vanilla cars to feel somewhere between tdu2 and tdu1 hc. Time trials and license tests will become relatively more challenging.
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Controller Hardcore Lite Example
{ "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":false, "steering_velocity":900.0, "steering_max_angle":40.0, "d6":"analog settings (controller configuration), applies on change", "override_analog_settings":false, "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":0.0, "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":1.0, "suspension_length_rear":1.0, "spring_front":0.75, "spring_rear":0.75, "dampers_front":0.75, "dampers_rear":0.75, "ride_height_front":1.0, "ride_height_rear":1.0, "anti_roll_bar_front":2.5, "anti_roll_bar_rear":2.5, "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":0.65, "lateral_grip_rear":0.65, "grip_front":0.7, "grip_rear":0.7, "brake_power":1.0 }, "ffb_tweaks": { "d1":"force feedback tweaks, applies on change", "enabled": false, "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 } } Wheel Hardcore Lite 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":1.0, "suspension_length_rear":1.0, "spring_front":0.75, "spring_rear":0.75, "dampers_front":0.75, "dampers_rear":0.75, "ride_height_front":1.0, "ride_height_rear":1.0, "anti_roll_bar_front":2.5, "anti_roll_bar_rear":2.5, "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":0.65, "lateral_grip_rear":0.65, "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 } }  
Changed values are logged in tdu2_physics_tweaks_log.txt for db tuning reference.
When log_effects under ffb_tweaks is enabled, effects sent to dinput8 are logged to dinput8_ffb_tweaks_log.txt
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Trouble shooting
Make sure your edited config is a valid json file and contains all the keys this tool needs.
Check tdu2_physics_tweaks_log.txt if the game refuses to start/self closes.
If tdu2_physics_tweaks_log.txt or dinput8_ffb_tweaks_log.txt don't change / don't get created, make sure the directory and the log files are not readonly.
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Building
On windows, install cygwin, along with mingw64-i686-gcc-core and mingw64-i686-gcc-g++ toolchains, then run build.sh at the project root in cygwin shell.
On linux, install podman from your package manager then run build_podman.sh.
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Credits
TDU2VPE https://turboduck.net/forums/topic/33748-tdu2vpe-release/ I would not know where to start at all without TDU2VPE tdudec https://aluigi.altervista.org/papers.htm For Physics.cpr encryption and decryption Xarlith https://turboduck.net/profile/15055-xarlith/ Tips on suspension adjustments MeFisto94 https://github.com/MeFisto94 https://turboduck.net/profile/38775-mefisto94/ Tips on suspension adjustments ---
External projects used
MinHook https://github.com/TsudaKageyu/minhook json https://github.com/nlohmann/json Ultimate-ASI-Loader https://github.com/ThirteenAG/Ultimate-ASI-Loader

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If you like this and would like to tip me, feel free to do so at https://ko-fi.com/kethen