FConstraintProfileProperties Struct Reference

#include <ConstraintInstance.h>

Public Member Functions
ENGINE_API	FConstraintProfileProperties ()
ENGINE_API void	Update_AssumesLocked (const FPhysicsConstraintHandle &InConstraintRef, float AverageMass, float UseScale, bool InInitialize=false) const
ENGINE_API void	UpdateBreakable_AssumesLocked (const FPhysicsConstraintHandle &InConstraintRef) const
ENGINE_API void	UpdatePlasticity_AssumesLocked (const FPhysicsConstraintHandle &InConstraintRef) const
ENGINE_API void	UpdateContactTransferScale_AssumesLocked (const FPhysicsConstraintHandle &InConstraintRef) const
ENGINE_API void	UpdateConstraintFlags_AssumesLocked (const FPhysicsConstraintHandle &InConstraintRef) const

Public Attributes
float	ProjectionLinearTolerance
float	ProjectionAngularTolerance
float	ProjectionLinearAlpha
float	ProjectionAngularAlpha
float	ShockPropagationAlpha
float	LinearBreakThreshold
float	LinearPlasticityThreshold
float	AngularBreakThreshold
float	AngularPlasticityThreshold
float	ContactTransferScale
FLinearConstraint	LinearLimit
FConeConstraint	ConeLimit
FTwistConstraint	TwistLimit
uint8	bDisableCollision: 1
uint8	bParentDominates: 1
uint8	bEnableShockPropagation: 1
uint8	bEnableProjection: 1
uint8	bEnableMassConditioning: 1
uint8	bUseLinearJointSolver: 1
uint8	bAngularBreakable: 1
uint8	bAngularPlasticity: 1
uint8	bLinearBreakable: 1
uint8	bLinearPlasticity: 1
FLinearDriveConstraint	LinearDrive
FAngularDriveConstraint	AngularDrive
TEnumAsByte< enum EConstraintPlasticityType >	LinearPlasticityType

Detailed Description

Container for properties of a physics constraint that can be easily swapped at runtime. This is useful for switching different setups when going from ragdoll to standup for example

Constructor & Destructor Documentation

FConstraintProfileProperties()

FConstraintProfileProperties::FConstraintProfileProperties

(

)

Member Function Documentation

Update_AssumesLocked()

void FConstraintProfileProperties::Update_AssumesLocked	(	const FPhysicsConstraintHandle &	InConstraintRef,
		float	AverageMass,
		float	UseScale,
		bool	InInitialize = false
	)		const

Updates physx joint properties from unreal properties (limits, drives, flags, etc...)

UpdateBreakable_AssumesLocked()

void FConstraintProfileProperties::UpdateBreakable_AssumesLocked

(

const FPhysicsConstraintHandle &

InConstraintRef

)

const

Updates joint breakable properties (threshold, etc...)

UpdateConstraintFlags_AssumesLocked()

void FConstraintProfileProperties::UpdateConstraintFlags_AssumesLocked

(

const FPhysicsConstraintHandle &

InConstraintRef

)

const

Updates joint flag based on profile properties

UpdateContactTransferScale_AssumesLocked()

void FConstraintProfileProperties::UpdateContactTransferScale_AssumesLocked

(

const FPhysicsConstraintHandle &

InConstraintRef

)

const

Updates joint linear mass scales.

UpdatePlasticity_AssumesLocked()

void FConstraintProfileProperties::UpdatePlasticity_AssumesLocked

(

const FPhysicsConstraintHandle &

InConstraintRef

)

const

Updates joint breakable properties (threshold, etc...)

Member Data Documentation

AngularBreakThreshold

float FConstraintProfileProperties::AngularBreakThreshold

Torque needed to break the joint.

AngularDrive

FAngularDriveConstraint FConstraintProfileProperties::AngularDrive

AngularPlasticityThreshold

float FConstraintProfileProperties::AngularPlasticityThreshold

[Chaos Only] Degree threshold from target angle needed to reset the target angle.

bAngularBreakable

uint8 FConstraintProfileProperties::bAngularBreakable

Whether it is possible to break the joint with angular force.

bAngularPlasticity

uint8 FConstraintProfileProperties::bAngularPlasticity

Whether it is possible to reset target rotations from the angular displacement.

bDisableCollision

uint8 FConstraintProfileProperties::bDisableCollision

bEnableMassConditioning

uint8 FConstraintProfileProperties::bEnableMassConditioning

Whether mass conditioning is enabled for this joint. Mass conditioning applies a non-physical scale to the mass and inertia of the two bodies that only affects this joint, so that the mass and inertia ratios are smaller. This helps stabilize joints where the bodies are very different sizes, and especially when the parent body is heavier than the child. However, it can lead to unrealistic behaviour, especially when collisions are involved.

bEnableProjection

uint8 FConstraintProfileProperties::bEnableProjection

Projection is a post-solve position and angular fixup consisting of two correction procedures. First, if the constraint limits are exceeded by more that the Linear or Angular Tolerance, the bodies are teleported to eliminate the error. Second, if the constraint limits are exceeded by less than the tolerance, a semi-physical correction is applied, with the parent body in the constraint is treated as having infinite mass. The teleport tolerance are controlled by ProjectionLinearTolerance and ProjectionAngularTolerance. The semi-physical correction is controlled by ProjectionLinearAlpha and ProjectionAnguilarAlpha. You may have one, none, or both systems enabled at the same time.

Projection only works well if the chain is not interacting with other objects (e.g., through collisions) because the projection of the bodies in the chain will cause other constraints to be violated. Likewise, if a body is influenced by multiple constraints, then enabling projection on more than one constraint may lead to unexpected results - the "last" constraint would win but the order in which constraints are solved cannot be directly controlled.

Note that the semi-physical projection (ProjectionLinearAlpha and ProjectionAngularAlpha) is only applied to hard-limit constraints and not those with soft limits because the soft limit is the point at which the soft-constraint (spring) kicks in, and not really a limit on how far the joint can be separated.

bEnableShockPropagation

uint8 FConstraintProfileProperties::bEnableShockPropagation

Shock propagation increases the mass of the parent body for the last iteration of the position and velocity solve phases. This can help stiffen up joint chains, but is also prone to introducing energy down the chain especially at high alpha. It also does not work well if there are collisions on the bodies preventing the joints from correctly resolving - this can lead to jitter, especially if collision shock propagation is also enabled.

bLinearBreakable

uint8 FConstraintProfileProperties::bLinearBreakable

Whether it is possible to break the joint with linear force.

bLinearPlasticity

uint8 FConstraintProfileProperties::bLinearPlasticity

Whether it is possible to reset spring rest length from the linear deformation.

bParentDominates

uint8 FConstraintProfileProperties::bParentDominates

bUseLinearJointSolver

uint8 FConstraintProfileProperties::bUseLinearJointSolver

World Solver: Whether to use linear solver for this joint. Linear solver is faster and less accurate. The nonlinear solver is slower and more convergent.

ConeLimit

FConeConstraint FConstraintProfileProperties::ConeLimit

ContactTransferScale

float FConstraintProfileProperties::ContactTransferScale

[Chaos Only] Colliison transfer on parent from the joints child. Range is 0.0-MAX

LinearBreakThreshold

float FConstraintProfileProperties::LinearBreakThreshold

Force needed to break the distance constraint.

LinearDrive

FLinearDriveConstraint FConstraintProfileProperties::LinearDrive

LinearLimit

FLinearConstraint FConstraintProfileProperties::LinearLimit

LinearPlasticityThreshold

float FConstraintProfileProperties::LinearPlasticityThreshold

[Chaos Only] Percent threshold from center of mass distance needed to reset the linear drive position target. This value can be greater than 1.

LinearPlasticityType

TEnumAsByte<enum EConstraintPlasticityType> FConstraintProfileProperties::LinearPlasticityType

Whether linear plasticity has a operation mode [free]

ProjectionAngularAlpha

float FConstraintProfileProperties::ProjectionAngularAlpha

How much semi-physical angular projection correction to apply [0-1]. Only used if bEnableProjection is true and if hard limits are used.

ProjectionAngularTolerance

float FConstraintProfileProperties::ProjectionAngularTolerance

If the joint error is above this distance after the solve phase, the child body will be teleported to fix the error. Only used if bEnableProjection is true.

ProjectionLinearAlpha

float FConstraintProfileProperties::ProjectionLinearAlpha

How much semi-physical linear projection correction to apply [0-1]. Only used if bEnableProjection is true and if hard limits are used.

ProjectionLinearTolerance

float FConstraintProfileProperties::ProjectionLinearTolerance

If the joint error is above this distance after the solve phase, the child body will be teleported to fix the error. Only used if bEnableProjection is true.

ShockPropagationAlpha

float FConstraintProfileProperties::ShockPropagationAlpha

How much shock propagation to apply [0-1]. Shock propagation increases the mass of the parent body for the last iteration of the position and velocity solve phases. This can help stiffen up joint chains, but is also prone to introducing energy down the chain especially at high alpha. Only used in bEnableShockPropagation is true.

TwistLimit

FTwistConstraint FConstraintProfileProperties::TwistLimit

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

• Engine/Source/Runtime/Engine/Classes/PhysicsEngine/ConstraintInstance.h
• Engine/Source/Runtime/Engine/Private/PhysicsEngine/ConstraintInstance.cpp