Class Powertrain

Coordinates the drivetrain from engine to wheels.

Inheritance
object
VehicleComponent
ManagerVehicleComponent
Powertrain
Inherited Members
Namespace: NWH.VehiclePhysics2.Powertrain
Assembly: NWH.VehiclePhysics2.dll
Syntax
[Serializable]
public class Powertrain : ManagerVehicleComponent
Remarks

Components form a directed graph linked by name: engine to clutch to transmission, splitting through differentials to the wheels. Each contributes its own inertia and losses. The solver runs two passes per step: angular velocity is queried backward from the wheels to the engine, then torque is propagated forward from the engine to the wheels.

Fields

clutch

Clutch component that manages power transmission between engine and transmission.

Declaration
public ClutchComponent clutch
Field Value
Type Description
ClutchComponent

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

2WD is a single differential feeding two wheels. AWD is three: a centre differential splitting to a front and a rear one, each of which splits left/right.

engine

Engine component that generates rotational power from throttle input.

Declaration
public EngineComponent engine
Field Value
Type Description
EngineComponent

transmission

Transmission component that adjusts gear ratios to optimize power delivery.

Declaration
public TransmissionComponent transmission
Field Value
Type Description
TransmissionComponent

wheelCount

Total number of wheels in the powertrain system.

Declaration
public int wheelCount
Field Value
Type Description
int
Remarks

Cached at initialization, so it is 0 or stale in edit mode. Counts every wheel, powered or not.

wheelGroupCount

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

Declaration
public int wheelGroupCount
Field Value
Type Description
int

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

A group carries the steering, brake and handbrake coefficients plus the Ackermann setting for its axle. Typical car: front (steer 1.0, brake 1.0), rear (steer 0, brake 0.7, handbrake 1.0). Multi-axle trucks add middle groups in between.

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

Order is by Z (front first) then X (left first), so a 4-wheel car reads FL, FR, RL, RR. Differential connections and wheel group assignment both rely on that order.

Methods

BreakOutputCycles()

Walks every output subgraph and clears any link that closes a loop.

Declaration
public void BreakOutputCycles()
Remarks

All four solver passes recurse into their outputs unconditionally, so a loop wired in the inspector (the output dropdown lists upstream components too) recurses until StackOverflowException, which the CLR cannot catch and which takes the process down with no log. Links are resolved by name/hash rather than by reference so this works before the components have resolved their own references.

FillComponentList()

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

Declaration
protected override void FillComponentList()
Overrides

FillInWheels()

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

Declaration
public void FillInWheels()
Remarks

Sorts the hierarchy's WheelControllers front-to-back, left-to-right and drops them into the existing wheel slots. Warns if the counts do not match.

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

Sorted by local Z (front first) then local X (left first), giving FL, FR, RL, RR on a 4-wheel car. Differential connections and wheel group assignment depend on that order.

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

Legacy lookup path for restoring serialized links at initialization.

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

Editor use only: allocates strings on every call.

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 leading null is deliberate: it lines up with the "[none]" entry from Inspector_GetPowertrainComponentNames so the two lists can be indexed together.

Repair()

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

Declaration
public void Repair()

VC_Enable(bool)

Enables manager and all children (with calledByParent=true).

Declaration
public override bool VC_Enable(bool calledByParent)
Parameters
Type Name Description
bool calledByParent
Returns
Type Description
bool
Overrides

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

VC_Initialize()

One-time setup, once per vehicle startup and after the VehicleController reference is set. Sets state.initialized on completion; an override that fails must leave it false.

Declaration
protected override void VC_Initialize()
Overrides

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

VC_SetDefaults()

Resets manager and all children to defaults.

Declaration
public override void VC_SetDefaults()
Overrides

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

See Also