#include <AnimPhysicsSolver.h>

Static Public Member Functions
static ENGINE_API float	CalculateVolume (const TArray< FVector > &InVertices, const TArray< FIntVector > &InTriangles)

static ENGINE_API float	CalculateVolume (const TArray< FAnimPhysShape > &InShapes)

static ENGINE_API FVector	CalculateCenterOfMass (const TArray< FVector > &InVertices, const TArray< FIntVector > &InTriangles)

static ENGINE_API FVector	CalculateCenterOfMass (const TArray< FAnimPhysShape > &InShapes)

static ENGINE_API FMatrix	CalculateInertia (const TArray< FVector > &InVertices, const TArray< FIntVector > &InTriangles, const FVector &InCenterOfMass)

static ENGINE_API FMatrix	CalculateInertia (const TArray< FAnimPhysShape > &InShapes, const FVector &InCenterOfMass)

static ENGINE_API void	ScaleRigidBodyMass (FAnimPhysRigidBody *InOutRigidBody, float Scale)

static ENGINE_API void	ApplyImpulse (FAnimPhysRigidBody *InOutRigidBody, const FVector &InWorldOrientedImpactPoint, const FVector &InImpulse)

static ENGINE_API void	PhysicsUpdate (float DeltaTime, TArray< FAnimPhysRigidBody * > &Bodies, TArray< FAnimPhysLinearLimit > &LinearLimits, TArray< FAnimPhysAngularLimit > &AngularLimits, TArray< FAnimPhysSpring > &Springs, const FVector &GravityDirection, const FVector &ExternalForce, const FVector &ExternalLinearAcc, const FVector &ExternalAngularAcc, const FVector &ExternalAngularVelocity, int32 NumPreIterations=8, int32 NumPostIterations=2)

static ENGINE_API void	ConstrainAlongDirection (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody FirstBody, const FVector &FirstPosition, FAnimPhysRigidBody SecondBody, const FVector &SecondPosition, const FVector &AxisToConstrain, const FVector2D Limits, float MinimumForce=-MAX_flt, float MaximumForce=MAX_flt)

static ENGINE_API void	ConstrainPositionNailed (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody FirstBody, const FVector &FirstPosition, FAnimPhysRigidBody SecondBody, const FVector &SecondPosition)

static ENGINE_API void	ConstrainPositionPrismatic (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody FirstBody, const FVector &FirstPosition, FAnimPhysRigidBody SecondBody, const FVector &SecondPosition, const FQuat &PrismRotation, const FVector &LimitsMin, const FVector &LimitsMax)

static ENGINE_API void	ConstrainAngularRange (float DeltaTime, TArray< FAnimPhysAngularLimit > &LimitContainer, FAnimPhysRigidBody FirstBody, FAnimPhysRigidBody SecondBody, const FQuat &JointFrame, AnimPhysTwistAxis TwistAxis, const FVector &JointLimitMin, const FVector &JointLimitMax, float InJointBias)

static ENGINE_API void	ConstrainConeAngle (float DeltaTime, TArray< FAnimPhysAngularLimit > &LimitContainer, FAnimPhysRigidBody FirstBody, const FVector &Normal0, FAnimPhysRigidBody SecondBody, const FVector &Normal1, float LimitAngle, float InJointBias)

static ENGINE_API void	ConstrainPlanar (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody *Body, const FTransform &PlaneTransform)

static ENGINE_API void	ConstrainSphericalInner (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody *Body, const FTransform &SphereTransform, float SphereRadius)

static ENGINE_API void	ConstrainSphericalOuter (float DeltaTime, TArray< FAnimPhysLinearLimit > &LimitContainer, FAnimPhysRigidBody *Body, const FTransform &SphereTransform, float SphereRadius)

static ENGINE_API void	CreateSpring (TArray< FAnimPhysSpring > &SpringContainer, FAnimPhysRigidBody Body0, FVector Position0, FAnimPhysRigidBody Body1, FVector Position1)

Static Public Attributes
static ENGINE_API bool	bEnableDetailedStats = false

static ENGINE_API float	CoriolisAlpha = 0.5f

static ENGINE_API float	CentrifugalAlpha = 1.0f

static ENGINE_API float	EulerAlpha = 1.0f

static constexpr float	AngularAccelerationAlpha = 1.0f

Detailed Description

Lightweight rigid body motion solver (no collision) used for cosmetic secondary motion in an animation graph without invoking something heavier like using PhysX to simulate constraints which could be cost prohibitive

Member Function Documentation

◆ ApplyImpulse()

void FAnimPhys::ApplyImpulse	(	FAnimPhysRigidBody *	InOutRigidBody,
		const FVector &	InWorldOrientedImpactPoint,
		const FVector &	InImpulse
	)

static

Apply an impulse to a body

Parameters

InOutRigidBody	Body to apply the impulse to
InWorldOrientedImpactPoint	Location of the impulse
InImpulse	Impulse to apply

◆ CalculateCenterOfMass() [1/2]

FVector FAnimPhys::CalculateCenterOfMass ( const TArray< FAnimPhysShape > & InShapes )

static

Calculates the centre of mass of a collection of shapes

Parameters

InShapes Collection of shapes to use

◆ CalculateCenterOfMass() [2/2]

FVector FAnimPhys::CalculateCenterOfMass	(	const TArray< FVector > &	InVertices,
		const TArray< FIntVector > &	InTriangles
	)

static

Calculates the center of mass of a shape

Parameters

InVertices	Verts in the shape
InTriangles	Triangles represented in InVertices

◆ CalculateInertia() [1/2]

FMatrix FAnimPhys::CalculateInertia	(	const TArray< FAnimPhysShape > &	InShapes,
		const FVector &	InCenterOfMass
	)

static

Calculate the inertia tensor of a collection of shapes

Parameters

InShapes	Shapes to use
InCenterOfMass	Center of mass of the collection

◆ CalculateInertia() [2/2]

FMatrix FAnimPhys::CalculateInertia	(	const TArray< FVector > &	InVertices,
		const TArray< FIntVector > &	InTriangles,
		const FVector &	InCenterOfMass
	)

static

Calculate the inertia tensor of a shape

Parameters

InVertices	Verts in the shape
InTriangles	Triangles represented in InVertices
InCenterOfMass	Center of mass of the shape

◆ CalculateVolume() [1/2]

float FAnimPhys::CalculateVolume ( const TArray< FAnimPhysShape > & InShapes )

static

Calculates the volume of a collection of shapes

Parameters

InShapes Collection of shapes to use

◆ CalculateVolume() [2/2]

float FAnimPhys::CalculateVolume	(	const TArray< FVector > &	InVertices,
		const TArray< FIntVector > &	InTriangles
	)

static

Calculates the volume of a shape

Parameters

InVertices	Verts in the shape
InTriangles	Triangles represented in InVertices

◆ ConstrainAlongDirection()

void FAnimPhys::ConstrainAlongDirection	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	FirstBody,
		const FVector &	FirstPosition,
		FAnimPhysRigidBody *	SecondBody,
		const FVector &	SecondPosition,
		const FVector &	AxisToConstrain,
		const FVector2D	Limits,
		float	MinimumForce = `-MAX_flt`,
		float	MaximumForce = `MAX_flt`
	)

static

Constrain bodies along a provided axis

Parameters

LimitContainer	Container to add limits to
FirstBody	First body in constraint (or nullptr for world)
FirstPosition	Local position on first body to apply constraint
SecondBody	Second body in constraint
SecondPosition	Local position on second body to apply constraint
AxisToConstrain	Axis to constrain between bodies
Limits	Limit on the provided axis so that Limits.X(min) < Final Position < Limits.Y(max)
MinimumForce	Minimum force that can be applied to satisfy the maximum limit (default -MAX_flt)
MaximumForce	Maximum force that can be applied to satisfy the minimum limit (default MAX_flt)

◆ ConstrainAngularRange()

void FAnimPhys::ConstrainAngularRange	(	float	DeltaTime,
		TArray< FAnimPhysAngularLimit > &	LimitContainer,
		FAnimPhysRigidBody *	FirstBody,
		FAnimPhysRigidBody *	SecondBody,
		const FQuat &	JointFrame,
		AnimPhysTwistAxis	TwistAxis,
		const FVector &	JointLimitMin,
		const FVector &	JointLimitMax,
		float	InJointBias
	)

static

Constraint two bodies together with angular limits, limiting the relative rotation between them. Note that this allows TWO axes to rotate, the twist axis will always be locked

Parameters

LimitContainer	Container to add limits to
FirstBody	First body in the constraint (or nullptr for world)
SecondBody	Second body in constraint
JointFrame	Frame/Rotation of the joint
TwistAxis	The axis to regard as the twist axis
JointLimitMin	Minimum limits along each axis (twist axis ignored)
JointLimitMax	Maximum limits along each axis (twist axis ignored)
InJointBias	Bias towards second body's forces (1.0f = 100%)

◆ ConstrainConeAngle()

void FAnimPhys::ConstrainConeAngle	(	float	DeltaTime,
		TArray< FAnimPhysAngularLimit > &	LimitContainer,
		FAnimPhysRigidBody *	FirstBody,
		const FVector &	Normal0,
		FAnimPhysRigidBody *	SecondBody,
		const FVector &	Normal1,
		float	LimitAngle,
		float	InJointBias
	)

static

Constraints the rotation between two bodies into a cone

Parameters

LimitContainer	Container to add limits to
FirstBody	First body in the constraint (or nullptr for world)
Normal0	Normal for the first side of the constraint
SecondBody	Second body in the constraint
Normal1	Normal for the second side of the constraint
LimitAngle	Angle to limit the cone to
InJointBias	Bias towards second body's forces (1.0f = 100%)

◆ ConstrainPlanar()

void FAnimPhys::ConstrainPlanar	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	Body,
		const FTransform &	PlaneTransform
	)

static

Constrains the position of a body to one side of a plane placed at PlaneTransform (plane normal is Z axis)

Parameters

LimitContainer	Container to add limits to
Body	The body to constrain to the plane
PlaneTransform	Transform of the plane, with the normal facing along the Z axis of the orientation

◆ ConstrainPositionNailed()

void FAnimPhys::ConstrainPositionNailed	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	FirstBody,
		const FVector &	FirstPosition,
		FAnimPhysRigidBody *	SecondBody,
		const FVector &	SecondPosition
	)

static

Constrain bodies together as if fixed or nailed (linear only, bodies can still rotate)

Parameters

LimitContainer	Container to add limits to
FirstBody	First body in constraint (or nullptr for world)
FirstPosition	Local position on first body to apply constraint
SecondBody	Second body in constraint
SecondPosition	Local position on second body to apply constraint

◆ ConstrainPositionPrismatic()

void FAnimPhys::ConstrainPositionPrismatic	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	FirstBody,
		const FVector &	FirstPosition,
		FAnimPhysRigidBody *	SecondBody,
		const FVector &	SecondPosition,
		const FQuat &	PrismRotation,
		const FVector &	LimitsMin,
		const FVector &	LimitsMax
	)

static

Constrain bodies together with linear limits forming a box or prism around the constraint

Parameters

LimitContainer	Container to add limits to
FirstBody	First body in the constraint (or nullptr for world)
FirstPosition	Local position on first body to apply constraint
SecondBody	Second body in the constraint
SecondPosition	Local position on the second body to apply constraint
PrismRotation	Rotation to apply to the prism axes, only necessary when constraining to world, otherwise the rotation of the first body is used
LimitsMin	Minimum limits along axes
LimitsMax	Maximum limits along axes

◆ ConstrainSphericalInner()

void FAnimPhys::ConstrainSphericalInner	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	Body,
		const FTransform &	SphereTransform,
		float	SphereRadius
	)

static

Constrains the position of a body within the requested sphere

◆ ConstrainSphericalOuter()

void FAnimPhys::ConstrainSphericalOuter	(	float	DeltaTime,
		TArray< FAnimPhysLinearLimit > &	LimitContainer,
		FAnimPhysRigidBody *	Body,
		const FTransform &	SphereTransform,
		float	SphereRadius
	)

static

Constrains the position of a body outside of the requested sphere

◆ CreateSpring()

void FAnimPhys::CreateSpring	(	TArray< FAnimPhysSpring > &	SpringContainer,
		FAnimPhysRigidBody *	Body0,
		FVector	Position0,
		FAnimPhysRigidBody *	Body1,
		FVector	Position1
	)

static

◆ PhysicsUpdate()

void FAnimPhys::PhysicsUpdate	(	float	DeltaTime,
		TArray< FAnimPhysRigidBody * > &	Bodies,
		TArray< FAnimPhysLinearLimit > &	LinearLimits,
		TArray< FAnimPhysAngularLimit > &	AngularLimits,
		TArray< FAnimPhysSpring > &	Springs,
		const FVector &	GravityDirection,
		const FVector &	ExternalForce,
		const FVector &	ExternalLinearAcc,
		const FVector &	ExternalAngularAcc,
		const FVector &	ExternalAngularVelocity,
		int32	NumPreIterations = `8`,
		int32	NumPostIterations = `2`
	)

static

Performs a physics update on the provided state objects

Parameters

DeltaTime	Time for the frame / update
Bodies	Bodies to integrate
LinearLimits	Linear limits to apply to the bodies
AngularLimits	Angular limits to apply to the bodies
Springs	Linear/Angular springs to apply to the bodies prior to solving
NumPreIterations	Number of times to iterate the limits before performing the integration
NumPostIterations	Number of times to iterae the limits after performing the integration

◆ ScaleRigidBodyMass()

void FAnimPhys::ScaleRigidBodyMass	(	FAnimPhysRigidBody *	InOutRigidBody,
		float	Scale
	)

static

Scale the mass and inertia properties of a rigid body

Parameters

InOutRigidBody	Body to modify
Scale	Scale to use

Member Data Documentation

◆ AngularAccelerationAlpha

constexpr float FAnimPhys::AngularAccelerationAlpha = 1.0f

staticconstexpr

◆ bEnableDetailedStats

bool FAnimPhys::bEnableDetailedStats = false

static

◆ CentrifugalAlpha

float FAnimPhys::CentrifugalAlpha = 1.0f

static

◆ CoriolisAlpha

float FAnimPhys::CoriolisAlpha = 0.5f

static

◆ EulerAlpha

float FAnimPhys::EulerAlpha = 1.0f

static

The documentation for this class was generated from the following files:

Engine/Source/Runtime/Engine/Public/Animation/AnimPhysicsSolver.h
Engine/Source/Runtime/Engine/Private/Animation/AnimPhysicsSolver.cpp

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Function Documentation

◆ ApplyImpulse()

◆ CalculateCenterOfMass() [1/2]

◆ CalculateCenterOfMass() [2/2]

◆ CalculateInertia() [1/2]

◆ CalculateInertia() [2/2]

◆ CalculateVolume() [1/2]

◆ CalculateVolume() [2/2]

◆ ConstrainAlongDirection()

◆ ConstrainAngularRange()

◆ ConstrainConeAngle()

◆ ConstrainPlanar()

◆ ConstrainPositionNailed()

◆ ConstrainPositionPrismatic()

◆ ConstrainSphericalInner()

◆ ConstrainSphericalOuter()

◆ CreateSpring()

◆ PhysicsUpdate()

◆ ScaleRigidBodyMass()

Member Data Documentation

◆ AngularAccelerationAlpha

◆ bEnableDetailedStats

◆ CentrifugalAlpha

◆ CoriolisAlpha

◆ EulerAlpha