UMjPassthroughController

Writes control values directly to d->ctrl without modification.

Use this when the MJCF actuators handle their own dynamics (position actuators with kp/kv, or motor actuators receiving raw torque from Python). Functionally identical to the default ApplyControls() path, but as an explicit component for consistency with the controller framework.

Attribute	Value
Kind	Class
UE Macro	UCLASS
Inherits	UMjArticulationController
Blueprint Spawnable	✅ Yes

Properties Functions

Properties

Public Properties

Property	Type	Description
bEnabled	bool	Is this controller active? If false, ApplyControls falls through to default path.

bEnabled

Is this controller active? If false, ApplyControls falls through to default path.

• Type: bool
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Controller

Protected Properties

Property	Type	Description
Bindings	TArray<FActuatorBinding>	Actuator→DOF bindings, populated by Bind().

Bindings

Actuator→DOF bindings, populated by Bind().

• Type: TArray<FActuatorBinding>

Functions

Public Functions

General

Function	Returns	Description
Bind()	void	Called once after the MuJoCo model compiles. Resolves actuator→DOF
ComputeAndApply()	void	Called every physics step from AMjArticulation::ApplyControls().
IsBound()	bool	Has Bind() been called successfully?
GetNumBindings()	int32	Number of bound actuators.
GetBindings()	const TArray<FActuatorBinding>&	Access bindings (for gain configuration by name).
GetKindName()	FString	Short kind name reported in the handshake (e.g. "pd", "passthrough").
GetConfigSchema()	void	Fill @p OutSchema with the JSON schema for this controller's params.
GetCurrentConfig()	void	Fill @p OutParams with the controller's current parameter values.
ApplyConfig()	void	Apply a partial JSON config to this controller. Missing fields keep their current value.

Bind

Called once after the MuJoCo model compiles. Resolves actuator→DOF

• Signature: Bind(mjModel* m, mjData* d, const TMapUMjActuator\*>& ActuatorIdMap)

ComputeAndApply

Called every physics step from AMjArticulation::ApplyControls().

• Signature: ComputeAndApply(mjModel* m, mjData* d, uint8 Source)

IsBound

Has Bind() been called successfully?

• Signature: IsBound()
• Returns: bool

GetNumBindings

Number of bound actuators.

• Signature: GetNumBindings()
• Returns: int32

GetBindings

Access bindings (for gain configuration by name).

• Signature: GetBindings()
• Returns: const TArray<FActuatorBinding>&

GetKindName

Short kind name reported in the handshake (e.g. "pd", "passthrough").

• Signature: GetKindName()
• Returns: FString

GetConfigSchema

Fill @p OutSchema with the JSON schema for this controller's params.

• Signature: GetConfigSchema(TSharedPtr<FJsonObject>& OutSchema)

GetCurrentConfig

Fill @p OutParams with the controller's current parameter values.

• Signature: GetCurrentConfig(TSharedPtr<FJsonObject>& OutParams)

ApplyConfig

Apply a partial JSON config to this controller. Missing fields keep their current value.

• Signature: ApplyConfig(const TSharedPtr<FJsonObject>& InParams)