iMSTK: imstk::PbdDistanceConstraint Class Reference

Distance constraints between two nodal points. More...

#include <imstkPbdDistanceConstraint.h>

Inheritance diagram for imstk::PbdDistanceConstraint:

Collaboration diagram for imstk::PbdDistanceConstraint:

Public Member Functions
void	initConstraint (const Vec3d &p0, const Vec3d &p1, const PbdParticleId &pIdx0, const PbdParticleId &pIdx1, const double k=1e5)
	Initialize the constraint with resting length as the length between the two points.

void	initConstraint (const double restLength, const PbdParticleId &pIdx0, const PbdParticleId &pIdx1, const double k=1e5)
	Initialize the constraint with provided resting length.

bool	computeValueAndGradient (PbdState &bodies, double &c, std::vector< Vec3d > &dcdx) override
	Compute value and gradient of the constraint. More...

double	getRestValue () const
	Return the rest configuration for the constraint.

Public Member Functions inherited from imstk::PbdConstraint
virtual const std::string	getTypeName () const =0

std::vector< PbdParticleId > &	getParticles ()
	Get the vertex indices of the constraint.

bool	getCorrectVelocity () const
	Get/Set whether velocity should be corrected for this constraint.

void	setCorrectVelocity (const bool correctVelocity)

const Vec3d &	getGradient (const int i) const
	Get gradient given the particle index in constraint.

double	getForce (const double dt) const
	Get the force magnitude, valid after solving lambda Only valid with xpbd.

double	getConstraintC () const
	Get constraint value C (how much the constraint is violated)

double	getLambda () const
	Get constraint value C (how much the constraint is violated)

void	zeroOutLambda ()
	Zero's out the lagrange multplier before integration only used for xpbd, must be called before solving.

virtual void	projectConstraint (PbdState &bodies, const double dt, const SolverType &type)
	Update positions by projecting constraints.

virtual void	correctVelocity (PbdState &bodies, const double dt)
	Correct velocities according to friction and restitution Corrects according to the gradient direction.

double	computeGeneralizedInvMass (const PbdState &bodies, const size_t particleIndex) const
	Compute generalized inverse mass of the particle. Note perf sensitive function. It has been intentionally inlined. More...

double	computeGeneralizedInvMass (const PbdState &bodies, const size_t particleIndex, const Vec3d &r) const
	Compute generalized inverse mass of the particle. More...

double	getRestitution () const
	Get/Set restitution.

void	setRestitution (const double restitution)

double	getFriction () const
	Get/Set friction.

void	setFriction (const double friction)

double	getStiffness () const
	Get/Set the stiffness.

void	setStiffness (const double stiffness)

double	getCompliance () const
	Get/Set the compliance This function is also provided in case users need 0 compliance.

void	setCompliance (const double compliance)

Public Attributes
double	m_restLength = 0.0
	Rest length between the nodes.

Additional Inherited Members
Public Types inherited from imstk::PbdConstraint
enum	SolverType { xPBD = 0, PBD }
	Type of solvers.

Protected Member Functions inherited from imstk::PbdConstraint
	PbdConstraint (const size_t numParticles)

Protected Attributes inherited from imstk::PbdConstraint
std::vector< PbdParticleId >	m_particles
	body, particle index

std::vector< Vec3d >	m_dcdx
	Normalized constraint gradients (per particle)

double	m_stiffness = 1.0
	used in PBD, [0, 1]

double	m_compliance = 1e-7
	used in xPBD, inverse of Stiffness

double	m_lambda = 0.0
	Lagrange multiplier.

double	m_C = 0.0
	Constraint Value.

double	m_friction = 0.0

double	m_restitution = 0.0

bool	m_correctVelocity = false