Class Powertrain

Main powertrain manager that coordinates the entire drivetrain system from engine to wheels.

Inheritance

object

VehicleComponent

ManagerVehicleComponent

Powertrain

Inherited Members

ManagerVehicleComponent._components

ManagerVehicleComponent.Components

ManagerVehicleComponent.AddAndOnboardNewComponent(VehicleComponent)

ManagerVehicleComponent.VC_LoadStateFromStateSettings()

ManagerVehicleComponent.VC_Update(float)

ManagerVehicleComponent.VC_Enable(bool)

ManagerVehicleComponent.VC_Disable(bool)

ManagerVehicleComponent.VC_DrawGizmos()

ManagerVehicleComponent.UpdateLOD()

VehicleComponent.state

VehicleComponent.vehicleController

VehicleComponent.IsActive

VehicleComponent.ToggleState()

Namespace: NWH.VehiclePhysics2.Powertrain

Assembly: NWH.VehiclePhysics2.dll

Syntax

[Serializable]
public class Powertrain : ManagerVehicleComponent

Remarks

The Powertrain class manages all powertrain components and their interconnections, forming a complete drivetrain simulation from the engine through clutch, transmission, differentials, and finally to the wheels. It handles component initialization, physics updates, and the torque flow through the entire system.

The powertrain architecture follows a graph-based structure where components are linked together in a chain. Torque flows from the engine (power source) through the clutch and transmission, then splits through differentials to reach the wheels (power sink). Each component contributes its inertia and losses to the overall system behavior.

Key responsibilities: - Managing engine, clutch, transmission, and differential components - Organizing wheels into logical groups for steering, braking, and differential connections - Coordinating physics updates through the powertrain solver - Handling component validation and default setup - Providing damage simulation and repair functionality

The powertrain solver uses a two-pass approach: first, angular velocities are queried backward from wheels to engine to determine component speeds; second, torque is propagated forward from engine to wheels to calculate forces. This bidirectional solving ensures accurate simulation of complex drivetrain interactions.

Fields

clutch

Clutch component that manages power transmission between engine and transmission.

Declaration

public ClutchComponent clutch

Field Value

Type	Description
ClutchComponent

Remarks

Controls engagement/disengagement and slip characteristics. Acts as the connection point between the engine's rotational output and the transmission input.

differentials

List of differential components that distribute torque between outputs (wheels or other differentials).

Declaration

public List<DifferentialComponent> differentials

Field Value

Type	Description
List<DifferentialComponent>

Remarks

Differentials allow wheels to rotate at different speeds during cornering while distributing torque. A typical vehicle setup includes front, rear, and center differentials connected in a hierarchy.

Common configurations: - 2WD: Single differential (front or rear) connected to two wheels - AWD: Three differentials - center splits power to front and rear, which each split to left/right wheels - 4WD: Similar to AWD but with different torque distribution characteristics

engine

Engine component that generates rotational power from throttle input.

Declaration

public EngineComponent engine

Field Value

Type	Description
EngineComponent

Remarks

The power source of the vehicle. Converts fuel/electric energy into rotational torque based on RPM, throttle position, and power curves. Includes starting, idle control, and rev limiting.

transmission

Transmission component that adjusts gear ratios to optimize power delivery.

Declaration

public TransmissionComponent transmission

Field Value

Type	Description
TransmissionComponent

Remarks

Multiplies engine torque through gear ratios to provide appropriate power at different speeds. Handles automatic or manual shifting, gear selection logic, and shift timing.

wheelCount

Total number of wheels in the powertrain system.

Declaration

public int wheelCount

Field Value

Type	Description
int

Remarks

Cached during initialization for performance. Includes all wheels connected to the powertrain regardless of whether they are powered, steered, or braked.

wheelGroupCount

Total number of wheel groups (axles) in the vehicle.

Declaration

public int wheelGroupCount

Field Value

Type	Description
int

Remarks

Each group typically represents an axle with shared properties like steering coefficient, brake distribution, and handbrake application.

wheelGroups

List of wheel groups that organize wheels into logical axles for steering, braking, and other control functions.

Declaration

public List<WheelGroup> wheelGroups

Field Value

Type	Description
List<WheelGroup>

Remarks

Wheel groups organize wheels that should share certain characteristics. Each group defines: - Steering coefficient (how much steering input affects this axle) - Brake coefficient (brake force distribution) - Handbrake coefficient (handbrake application strength) - Ackermann steering geometry settings

Typical setup: Front group (steering=1.0, brake=1.0), Rear group (steering=0, brake=0.7, handbrake=1.0). Multi-axle vehicles like trucks may have additional middle groups with intermediate values.

wheels

List of all wheel components in the powertrain, ordered front-to-back and left-to-right.

Declaration

public List<WheelComponent> wheels

Field Value

Type	Description
List<WheelComponent>

Remarks

Wheels are the final power sink in the powertrain chain. They convert rotational torque into linear motion through tire-ground interaction, and also provide resistance torque back to the engine.

Ordering convention: wheels are sorted by Z position (front first) then X position (left first). Example 4-wheel order: Front-Left, Front-Right, Rear-Left, Rear-Right. This ordering is important for consistent setup and differential connections.

Methods

FillComponentList()

Override to populate _components with your child components. Called lazily on first Components access.

Declaration

protected override void FillComponentList()

Overrides

ManagerVehicleComponent.FillComponentList()

FillInWheels()

Automatically finds and assigns WheelController components to the powertrain's wheel list.

Declaration

public void FillInWheels()

Remarks

Searches for all WheelController components in the vehicle hierarchy, sorts them in standard order (front-to-back, left-to-right), and assigns them to the existing wheel component slots. The number of found WheelControllers should match the wheelCount for proper operation. Used during vehicle setup to automatically connect wheels to the powertrain system.

GetSortedWheels(VehicleController)

Gets all WheelController components from the vehicle and sorts them in standard order.

Declaration

public static List<WheelController> GetSortedWheels(VehicleController vehicleController)

Parameters

Type	Name	Description
VehicleController	vehicleController	The vehicle controller to search for wheel controllers.

Returns

Type	Description
List<WheelController>	List of WheelController components sorted front-to-back (Z descending) then left-to-right (X ascending).

Remarks

The sorting order ensures consistent wheel identification and connection throughout the powertrain system. Wheels are first sorted by their local Z position (front wheels first), then by local X position (left wheels first).

Standard 4-wheel order: Front-Left, Front-Right, Rear-Left, Rear-Right. This ordering convention is important for proper differential connections and wheel group assignments.

Inspector_GetPowertrainComponentFromName(string)

Finds a powertrain component by its name string.

Declaration

public PowertrainComponent Inspector_GetPowertrainComponentFromName(string componentName)

Parameters

Type	Name	Description
string	componentName	Name of the component to search for.

Returns

Type	Description
PowertrainComponent	The PowertrainComponent with matching name, or null if not found.

Remarks

Preferred over Inspector_GetPowertrainComponentFromNameHash(int) for persisted link reconstruction since string comparison is stable across Unity versions while string.GetHashCode is not.

Inspector_GetPowertrainComponentFromNameHash(int)

Finds a powertrain component by its name hash code.

Declaration

public PowertrainComponent Inspector_GetPowertrainComponentFromNameHash(int nameHash)

Parameters

Type	Name	Description
int	nameHash	The hash code of the component's name to search for.

Returns

Type	Description
PowertrainComponent	The PowertrainComponent with matching name hash, or null if not found.

Remarks

Uses hash code comparison for fast component lookups when establishing connections between powertrain components. This is primarily used during initialization to restore serialized connections.

Inspector_GetPowertrainComponentNames()

Gets a list of all powertrain component names for inspector dropdown menus.

Declaration

public List<string> Inspector_GetPowertrainComponentNames()

Returns

Type	Description
List<string>	List of component names starting with "[none]" followed by engine, clutch, transmission, differentials, and wheels.

Remarks

This method is intended for inspector/editor use only as it performs string allocation which is not optimal for runtime. Used to populate dropdown menus when connecting powertrain components in the editor.

Inspector_GetPowertrainComponents()

Gets a list of all powertrain component references for inspector operations.

Declaration

public List<PowertrainComponent> Inspector_GetPowertrainComponents()

Returns

Type	Description
List<PowertrainComponent>	List of PowertrainComponent references with null as the first element, followed by all components.

Remarks

The first element is intentionally null to correspond with the "[none]" option in component name dropdowns. This allows index-based matching between component names and component references in the inspector.

Repair()

Repairs all powertrain components by resetting their damage values to zero.

Declaration

public void Repair()

Remarks

Instantly restores all powertrain components to full functionality. This includes the engine, clutch, transmission, all differentials, and all wheels. Useful for implementing repair mechanics, respawning vehicles, or resetting vehicle state.

VC_FixedUpdate(float)

Physics update for manager and all active children.

Declaration

public override void VC_FixedUpdate(float DeltaTime)

Parameters

Type	Name	Description
float	DeltaTime

Overrides

ManagerVehicleComponent.VC_FixedUpdate(float)

VC_Initialize()

Initializes the component's internal systems and resources. Called once during vehicle startup after the VehicleController reference is set.

Declaration

protected override void VC_Initialize()

Overrides

VehicleComponent.VC_Initialize()

Remarks

Override this to set up component-specific resources, cache references, or perform one-time initialization. Sets state.initialized to true on completion.

VC_Initialize(VehicleController)

Initializes manager and all children with VehicleController reference.

Declaration

public override void VC_Initialize(VehicleController vc)

Parameters

Type	Name	Description
VehicleController	vc

Overrides

ManagerVehicleComponent.VC_Initialize(VehicleController)

VC_SetDefaults()

Resets manager and all children to defaults.

Declaration

public override void VC_SetDefaults()

Overrides

ManagerVehicleComponent.VC_SetDefaults()

VC_Validate(VehicleController)

Validates manager and all enabled children. Skips if manager is disabled.

Declaration

public override void VC_Validate(VehicleController vc)

Parameters

Type	Name	Description
VehicleController	vc

Overrides

ManagerVehicleComponent.VC_Validate(VehicleController)