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Custom Gravity

This guide explains how to customize gravity direction.

Basic Gravity Settings​

UPROPERTY()
FVector Gravity = FVector(0, 0, -1.0f);

Default is downward (-Z direction) gravity.

Changing Gravity Direction​

World Coordinate Specification​

// Downward (default)
Gravity = FVector(0, 0, -1.0f);

// Forward direction
Gravity = FVector(1.0f, 0, 0);

// Diagonal down
Gravity = FVector(0.5f, 0, -0.5f).GetSafeNormal();

Character-Relative Specification​

Set dynamically in Blueprint:

// Use character's downward direction
FVector CharacterDown = -Character->GetActorUpVector();
KawaiiPhysicsNode->Gravity = CharacterDown;

Use Cases​

Wall-Walking Character​

When a character walks on walls, align gravity direction with the wall normal.

void UpdateGravity(FVector WallNormal)
{
    // Set opposite of wall normal as gravity
    Gravity = -WallNormal;
}

Outer Space​

Zero gravity environment:

Gravity = FVector::ZeroVector;

Underwater​

Express buoyancy:

// Upward buoyancy
Gravity = FVector(0, 0, 0.3f);

Gravity Per Body Part​

To apply different gravity to different parts, use multiple KawaiiPhysics nodes.

AnimGraph
├── KawaiiPhysics (Hair: normal gravity)
│   Gravity = (0, 0, -1)
│
└── KawaiiPhysics (Wings: upward buoyancy)
    Gravity = (0, 0, 0.2)

Dynamic Gravity Changes​

Gravity can be changed during gameplay.

// Blueprint callable function
UFUNCTION(BlueprintCallable)
void SetCustomGravity(FVector NewGravity)
{
    KawaiiPhysicsNode->Gravity = NewGravity;
}

For more details, see Runtime Control.