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freecloth::SimSimulator Class Reference

An implementation of Baraff & Witkin's cloth simulation algorithm. More...

#include <freecloth/simulator/simSimulator.h>

Inheritance diagram for freecloth::SimSimulator:

List of all members.

Public Types
enum	ForceType {   F_STRETCH, F_SHEAR, F_BEND, F_GRAVITY,   F_DRAG, NB_FORCES }
	The individual classes of forces.
Public Member Functions
	SimSimulator (const GeMesh &initialMesh)
const GeMesh &	getMesh () const
const RCShdPtr< GeMesh > &	getMeshPtr () const
void	rewind ()
void	step ()
BaTime::Instant	getTime () const
	Retrieve the current simulation time.
void	removeAllConstraints ()
	Remove all constraints on all vertices.
void	setPosConstraintPlane (GeMesh::VertexId, const GeVector &)
void	setPosConstraintLine (GeMesh::VertexId, const GeVector &)
	Constrain movement of the vertex to the given line.
void	setPosConstraintFull (GeMesh::VertexId)
	Completely constrain the vertex, allowing no movement.
void	setVelConstraint (GeMesh::VertexId, const GeVector &)
bool	subStepsDone () const
void	preSubSteps ()
void	subStep ()
void	postSubSteps ()
void	setTimestep (Float)
	Mutator.
void	setParams (const Params &)
	Mutator.
void	setDensity (Float rho)
	Mutator.
void	setPCGTolerance (Float)
	Mutator.
Float	getTimestep () const
	Accessor.
const Params &	getParams () const
	Accessor.
Float	getDensity () const
	Accessor.
Float	getPCGTolerance () const
	Accessor.
GeVector	getVelocity (GeMesh::VertexId vid) const
	Only exposed for debugging purposes.
GeVector	getForce (GeMesh::VertexId vid) const
	Only exposed for debugging purposes.
Float	getEnergy (ForceType) const
	Only exposed for debugging purposes.
Float	getTriEnergy (ForceType, GeMesh::FaceId) const
	Only exposed for debugging purposes.
GeVector	getForce (ForceType type, GeMesh::VertexId vid) const
	Only exposed for debugging purposes.
GeVector	getDampingForce (ForceType type, GeMesh::VertexId vid) const
	Only exposed for debugging purposes.
void	setMesh (const GeMesh &)
	Only exposed for debugging purposes.

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Detailed Description

An implementation of Baraff & Witkin's cloth simulation algorithm.

Using the simulation is fairly straightforward. The client supplies an initial mesh, which must have disc topology. The client also specifies the density of the cloth, which indirectly defines the mass of each triangle of the mesh. The client can also specify constraints on the cloth motion, constraining both the position and the velocity of individual nodes of the mesh.

Time starts at zero, and is advanced by a fixed timestep by calls to step(). The client can retrieve the mesh after each timestep. The simulation can be rewound to the beginning by calling rewind().

There are many parameters for the simulation algorithm. See [BarWit98] or the description in SimSimulator::Params for details.

References:

• [BarWit98] D. Baraff and A. Witkin. Large Steps in Cloth Simulation. SIGGRAPH Conference Proceedings, 1998, 43-54. http://www-2.cs.cmu.edu/~baraff/papers/sig98.pdf
• [Pri02] D. Pritchard. "Implementing Baraff & Witkin's Cloth Simulation". Unpublished, 2002. http://freecloth.enigmati.ca/docs/report-chaps/
• [Mac00] D. Macri. Real-Time Cloth. Game Developers Conference, 2000. http://www.gdconf.com/archives/2000/macri.doc

Definition at line 104 of file simSimulator.h.

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Member Function Documentation

void freecloth::SimSimulator::postSubSteps (    )

Finer grained simulation control - allows the client more control over the computation. See step() for details. Definition at line 608 of file simSimulator.cpp. Referenced by step().

void freecloth::SimSimulator::preSubSteps (    )

Finer grained simulation control - allows the client more control over the computation. See step() for details. Definition at line 482 of file simSimulator.cpp. References freecloth::SimSimulator::Params::_g, freecloth::SimSimulator::Params::_k_drag, freecloth::SimVector::clear(), and freecloth::SimVector::dot(). Referenced by step().

void freecloth::SimSimulator::rewind (    )

Rewind simulation time to zero, and return the mesh to its initial state. Definition at line 318 of file simSimulator.cpp. References ForceType.

void freecloth::SimSimulator::setPosConstraintPlane (  GeMesh::VertexId   , const GeVector &    )

Constrain movement of the vertex to the plane defined by the given normal. Definition at line 409 of file simSimulator.cpp. References freecloth::GeVector::getUnit().

void freecloth::SimSimulator::setVelConstraint (  GeMesh::VertexId   , const GeVector &    )

Force the vertex to move with the specified velocity. This overrides any position constraints. Definition at line 463 of file simSimulator.cpp. References freecloth::SimVector::size().

void freecloth::SimSimulator::step (    )

Advance the simulation by one timestep. step() is equivalent to calling preSubSteps() repeated subStep() calls postSubSteps() Definition at line 471 of file simSimulator.cpp. References postSubSteps(), preSubSteps(), subStep(), and subStepsDone().

void freecloth::SimSimulator::subStep (    )

Finer grained simulation control - allows the client more control over the computation. See step() for details. Definition at line 601 of file simSimulator.cpp. Referenced by step().

bool freecloth::SimSimulator::subStepsDone (    )  const

Finer grained simulation control - allows the client more control over the computation. See step() for details. Definition at line 594 of file simSimulator.cpp. Referenced by step().

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

• simSimulator.h
• simSimulator.cpp

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