External Forces Parameters

Parameters related to externally applied forces.

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Gravity

Gravity

Gravity - Gravity vector applied to bones.

Property	Value
Type	FVector
Default	(0, 0, 0)
Category	ExternalForce

// Apply downward gravity
Gravity = FVector(0, 0, -1.0f);

bUseLegacyGravity

Legacy Gravity Method - Specifies the Gravity application method.

Property	Value
Type	bool
Default	false
Category	ExternalForce

Value	Description
true	Legacy compatible (adds 0.5 * Gravity * dt^2 to position)
false	AnimDynamics compatible (adds Gravity * dt to velocity, then updates position)

bUseDefaultGravityZProjectSetting

Use Project Setting Gravity - Flag to multiply Gravity vector by the project setting's DefaultGravityZ (absolute value).

Property	Value
Type	bool
Default	false
Category	ExternalForce

bUseWorldSpaceGravity

World Space Gravity - Flag for whether to handle gravity in world coordinate system.

Property	Value
Type	bool
Default	true
Category	ExternalForce

Wind

bEnableWind

Enable Wind - Flag for whether to receive influence from WindDirectionalSource as external force.

Property	Value
Type	bool
Default	false
Category	ExternalForce

WindScale

Wind Scale - Influence degree of wind from WindDirectionalSource. Used for compatibility with Cloth and SpeedTree.

Property	Value
Type	float
Default	1.0
Category	ExternalForce

note

WindScale is only effective when bEnableWind is true.

WindDirectionNoiseAngle

Wind Direction Noise - Noise (angle) applied to wind direction from WindDirectionalSource.

Property	Value
Type	float
Default	0.0
Unit	Degrees
Range	0 or higher
Category	ExternalForce

Simple External Force

SimpleExternalForce

Simple External Force Vector - Allows applying force in any direction.

Property	Value
Type	FVector
Default	(0, 0, 0)
Category	ExternalForce

bUseWorldSpaceSimpleExternalForce

World Space External Force - Flag for whether to handle simple external force in world coordinate system.

Property	Value
Type	bool
Default	true
Category	ExternalForce

External Force Presets

ExternalForces

External Force Presets (Instanced Struct) - External force presets. Custom presets can be added in C++.

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "ExternalForce",
    meta = (BaseStruct = "/Script/KawaiiPhysics.KawaiiPhysics_ExternalForce", ExcludeBaseStruct))
TArray<FInstancedStruct> ExternalForces;

CustomExternalForces (Experimental)

Custom External Forces (Instanced Property) - Custom presets can be added in BP/C++.

UPROPERTY(EditAnywhere, BlueprintReadWrite, Instanced, Category = "ExternalForce")
TArray<TObjectPtr<UKawaiiPhysics_CustomExternalForce>> CustomExternalForces;

warning

This feature is highly experimental. It may not work properly unless you click on the AnimNode or compile the Animation Blueprint.

Tag

KawaiiPhysicsTag

Filtering Tag - GameplayTag for filtering, used with ExternalForce, etc.

Property	Value
Type	FGameplayTag
Category	Tag

// Apply external force using tag
FGameplayTagContainer FilterTags;
FilterTags.AddTag(FGameplayTag::RequestGameplayTag("KawaiiPhysics.Hair"));
UKawaiiPhysicsLibrary::AddExternalForcesToComponent(MeshComp, ExternalForces, Owner, FilterTags);

Blueprint API

External forces can be dynamically controlled from Blueprint.

Adding External Force

UFUNCTION(BlueprintCallable, Category = "Kawaii Physics")
static bool AddExternalForce(const FKawaiiPhysicsReference& KawaiiPhysics,
                             FInstancedStruct& ExternalForce, UObject* Owner, bool bIsOneShot = false);

Adding External Force to Component

UFUNCTION(BlueprintCallable, Category = "Kawaii Physics")
static bool AddExternalForcesToComponent(USkeletalMeshComponent* MeshComp,
                                         TArray<FInstancedStruct>& ExternalForces, UObject* Owner,
                                         FGameplayTagContainer& FilterTags,
                                         bool bFilterExactMatch = false,
                                         bool bIsOneShot = false);

Removing External Force

UFUNCTION(BlueprintCallable, Category = "Kawaii Physics")
static bool RemoveExternalForcesFromComponent(USkeletalMeshComponent* MeshComp, UObject* Owner,
                                              FGameplayTagContainer& FilterTags,
                                              bool bFilterExactMatch = false);

For more details, see UKawaiiPhysicsLibrary.