artisynth.core.mechmodels

Class AxialSpring

java.lang.Object

artisynth.core.modelbase.ModelComponentBase

artisynth.core.mechmodels.Spring

artisynth.core.mechmodels.PointSpringBase

artisynth.core.mechmodels.AxialSpring

All Implemented Interfaces:

ForceComponent, ForceEffector, ForceTargetComponent, CopyableComponent, HasNumericState, ModelComponent, PostScannable, RenderableComponent, ScalableUnits, java.lang.Cloneable, HasProperties, HierarchyNode, HasRenderProps, IsRenderable, IsSelectable, Renderable, Scannable

Direct Known Subclasses:

Muscle

public class AxialSpring
extends PointSpringBase
implements ScalableUnits, CopyableComponent, ForceTargetComponent

Nested Class Summary

Nested classes/interfaces inherited from interface artisynth.core.modelbase.ModelComponent

ModelComponent.FilePathSaveType, ModelComponent.NavpanelVisibility

Field Summary

Fields

Modifier and Type	Field and Description
static PropertyList	myProps

Fields inherited from class artisynth.core.mechmodels.PointSpringBase

myIgnoreCoriolisInJacobian, useMaterial

Fields inherited from class artisynth.core.modelbase.ModelComponentBase

enforceUniqueCompositeNames, enforceUniqueNames, myNumber, NULL_OBJ, useCompactPathNames

Fields inherited from interface artisynth.core.modelbase.CopyableComponent

COPY_REFERENCES, REST_POSITION

Fields inherited from interface maspack.render.IsRenderable

TRANSPARENT, TWO_DIMENSIONAL

Constructor Summary

Constructors

Constructor and Description
AxialSpring()
AxialSpring(double k, double d, double l0)
AxialSpring(java.lang.String name)
AxialSpring(java.lang.String name, double l0)
AxialSpring(java.lang.String name, double k, double d, double l0)

Method Summary

Modifier and Type	Method and Description
int	addForcePosJacobian(SparseBlockMatrix J, double h, boolean staticOnly, int bi) Add a row to the force Jacobian for this force target component.
int	addForceVelJacobian(SparseBlockMatrix J, double h, int bi)
void	addPosJacobian(SparseNumberedBlockMatrix M, double s) Scales the components of the position Jacobian associated with this force effector and adds it to the supplied solve matrix M.
void	addSolveBlocks(SparseNumberedBlockMatrix M) Adds any needed blocks to a solve matrix in order to accomodate the Jacobian terms associated with this force effector.
void	addVelJacobian(SparseNumberedBlockMatrix M, double s) Scales the components of the velocity Jacobian associated with this force effector and adds it to the supplied solve matrix M.
void	applyForces(double t) Adds forces to the components affected by this force effector at a particular time.
void	computeForce(Vector3d f) Computes the force acting on the first point.
void	computeForcePositionJacobian(Matrix3d M) Computes the force/position Jacobian of this spring.
void	computeForceVelocityJacobian(Matrix3d M) Computes the force/velocity Jacobian of this spring.
ModelComponent	copy(int flags, java.util.Map<ModelComponent,ModelComponent> copyMap) Create a copy of this component.
PropertyList	getAllPropertyInfo() Returns a list giving static information about all properties exported by this object.
boolean	getCopyReferences(java.util.List<ModelComponent> refs, ModelComponent ancestor) Collects external references which must also be copied in order to duplicate this component.
Vector3d	getDir()
Point	getFirstPoint()
void	getForce(VectorNd minf, boolean staticOnly)
int	getForceSize()
void	getHardReferences(java.util.List<ModelComponent> refs) Appends all hard references for this component to a list.
int	getJacobianType() Returns a code indicating the matrix type that results when the Jacobian terms of this force effector are added to the solve matrix.
double	getLength()
double	getLengthDot()
Point	getPoint(int idx) Returns the idx-th point in this spring.
Point	getSecondPoint()
int	indexOfPoint(Point pnt) Returns the index of a specified point in this spring, or -1 if the point is not present.
boolean	isDuplicatable() Returns true if this component can be duplicated.
int	numPoints() Queries the number of points in this spring.
void	printPointReferences(java.io.PrintWriter pw, CompositeComponent ancestor)
void	render(Renderer renderer, int flags) Render this object using the functionality of the supplied Renderer.
void	scaleDistance(double s) Scales all distance coordinates.
void	scaleMass(double s) Scales all mass units.
void	setFirstPoint(Point pnt)
void	setPoint(int idx, Point pnt) Sets a point at a particular index.
void	setPoints(Point p1, Point p2)
void	setPoints(Point p1, Point p2, double restLength)
double	setRestLengthFromPoints() Sets the rest length of the spring from the current point locations
void	setSecondPoint(Point pnt)
void	updateBounds(Vector3d pmin, Vector3d pmax) Update the minimum and maximum points for this object.
void	write(java.io.PrintWriter pw, NumberFormat fmt, java.lang.Object ref) Writes a text description of this element to a PrintWriter.

Methods inherited from class artisynth.core.mechmodels.PointSpringBase

advanceState, computeDFdl, computeDFdl, computeDFdldot, computeDFdldot, computeF, computeF, containsPoint, createDefaultMaterial, createRenderProps, getAuxVarDerivative, getAuxVarState, getEffectiveMaterial, getForceScaling, getMaterial, getMaxForce, getRenderColor, getRenderHints, getRenderProps, getRestLength, getSelection, getState, getStateVersion, hasState, isSelectable, normalizeForceScaling, numAuxVars, numSelectionQueriesNeeded, prerender, requiresAdvance, setAuxVarState, setDamping, setLinearMaterial, setMaterial, setMaxForce, setRenderProps, setRestLength, setState, setStiffness

Methods inherited from class artisynth.core.modelbase.ModelComponentBase

checkFlag, checkName, checkNameUniqueness, clearFlag, clone, connectToHierarchy, createTempFlag, disconnectFromHierarchy, getChildren, getGrandParent, getName, getNameRange, getNavpanelVisibility, getNavpanelVisibility, getNumber, getParent, getProperty, getSoftReferences, hasChildren, isFixed, isMarked, isScanning, isSelected, isWritable, makeValidName, makeValidName, notifyParentOfChange, postscan, printReferences, recursivelyContained, recursivelyContains, removeTempFlag, scan, setFixed, setFlag, setMarked, setName, setNavpanelVisibility, setNavpanelVisibility, setNumber, setParent, setScanning, setSelected, setWritable, updateReferences

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface artisynth.core.modelbase.ModelComponent

connectToHierarchy, disconnectFromHierarchy, getName, getNavpanelVisibility, getNumber, getParent, getSoftReferences, hasState, isFixed, isMarked, isSelected, notifyParentOfChange, scan, setFixed, setMarked, setName, setNumber, setParent, setSelected, setWritable, updateReferences

Methods inherited from interface maspack.properties.HasProperties

getProperty

Methods inherited from interface maspack.properties.HierarchyNode

getChildren, hasChildren

Methods inherited from interface artisynth.core.modelbase.PostScannable

postscan

Methods inherited from interface maspack.util.Scannable

isWritable

Field Detail

myProps

public static PropertyList myProps

Constructor Detail

AxialSpring

public AxialSpring()

AxialSpring

public AxialSpring(java.lang.String name)

AxialSpring

public AxialSpring(java.lang.String name,
                   double l0)

AxialSpring

public AxialSpring(java.lang.String name,
                   double k,
                   double d,
                   double l0)

AxialSpring

public AxialSpring(double k,
                   double d,
                   double l0)

Method Detail

getAllPropertyInfo

public PropertyList getAllPropertyInfo()

Description copied from interface: HasProperties

Returns a list giving static information about all properties exported by this object.

Specified by:

getAllPropertyInfo in interface HasProperties

Overrides:

getAllPropertyInfo in class PointSpringBase

Returns:

static information for all exported properties

getFirstPoint

public Point getFirstPoint()

getSecondPoint

public Point getSecondPoint()

setPoints

public void setPoints(Point p1,
                      Point p2)

setPoints

public void setPoints(Point p1,
                      Point p2,
                      double restLength)

setFirstPoint

public void setFirstPoint(Point pnt)

setSecondPoint

public void setSecondPoint(Point pnt)

numPoints

public int numPoints()

Queries the number of points in this spring.

Specified by:

numPoints in class PointSpringBase

Returns:

number of points in the spring

getPoint

public Point getPoint(int idx)

Returns the idx-th point in this spring.

Specified by:

getPoint in class PointSpringBase

Parameters:

idx - point index

Returns:

the idx-th point

setPoint

public void setPoint(int idx,
                     Point pnt)

Sets a point at a particular index. The index must be < numPoints().

Specified by:

setPoint in class PointSpringBase

Parameters:

idx - specifies point position

pnt - replacement point

indexOfPoint

public int indexOfPoint(Point pnt)

Returns the index of a specified point in this spring, or -1 if the point is not present.

Specified by:

indexOfPoint in class PointSpringBase

Parameters:

pnt - point whose index is desired

Returns:

index of the point, or -1 if not present

setRestLengthFromPoints

public double setRestLengthFromPoints()

Description copied from class: PointSpringBase

Sets the rest length of the spring from the current point locations

Specified by:

setRestLengthFromPoints in class PointSpringBase

Returns:

the new rest length

computeForce

public void computeForce(Vector3d f)

Computes the force acting on the first point. The force acting on the second point is the negative of this force.

Parameters:

f - returns the computed force acting on the first point

applyForces

public void applyForces(double t)

Description copied from interface: ForceEffector

Adds forces to the components affected by this force effector at a particular time. Component forces should be added and not set, since other forces may be added to the same components by other force effectors.

Specified by:

applyForces in interface ForceEffector

Specified by:

applyForces in class Spring

Parameters:

t - time (seconds)

printPointReferences

public void printPointReferences(java.io.PrintWriter pw,
                                 CompositeComponent ancestor)
                          throws java.io.IOException

Throws:

java.io.IOException

write

public void write(java.io.PrintWriter pw,
                  NumberFormat fmt,
                  java.lang.Object ref)
           throws java.io.IOException

Description copied from class: ModelComponentBase

Writes a text description of this element to a PrintWriter. The text description should be compatable with scan and complete enough to allow full reconstruction of the element.

Specified by:

write in interface Scannable

Overrides:

write in class ModelComponentBase

Parameters:

pw - stream for writing the element

fmt - numeric formating information

ref - optional reference object which can be used for producing references to other objects

Throws:

java.io.IOException - if an I/O error occured

updateBounds

public void updateBounds(Vector3d pmin,
                         Vector3d pmax)

Description copied from interface: IsRenderable

Update the minimum and maximum points for this object. In an x-y-z coordinate system with x directed to the right and y directed upwards, the minimum and maximum points can be thought of as defining the left-lower-far and right-upper-near corners of a bounding cube. This method should only reduce the elements of the minimum point and increase the elements of the maximum point, since it may be used as part of an iteration to determine the bounding cube for several different objects.

Specified by:

updateBounds in interface IsRenderable

Specified by:

updateBounds in class PointSpringBase

Parameters:

pmin - minimum point

pmax - maximum point

render

public void render(Renderer renderer,
                   int flags)

Description copied from interface: IsRenderable

Render this object using the functionality of the supplied Renderer.

Specified by:

render in interface IsRenderable

Specified by:

render in class PointSpringBase

Parameters:

renderer - provides the functionality used to perform the rendering.

flags - flags that may be used to control different aspects of the rendering. Flags are defined in Renderer and currently include Renderer.HIGHLIGHT and Renderer.SORT_FACES.

scaleDistance

public void scaleDistance(double s)

Description copied from interface: ScalableUnits

Scales all distance coordinates.

Specified by:

scaleDistance in interface ScalableUnits

Overrides:

scaleDistance in class PointSpringBase

Parameters:

s - scaling factor

scaleMass

public void scaleMass(double s)

Description copied from interface: ScalableUnits

Scales all mass units.

Specified by:

scaleMass in interface ScalableUnits

Overrides:

scaleMass in class PointSpringBase

Parameters:

s - scaling factor

getDir

public Vector3d getDir()

getLength

public double getLength()

Specified by:

getLength in class PointSpringBase

getLengthDot

public double getLengthDot()

Specified by:

getLengthDot in class PointSpringBase

computeForcePositionJacobian

public void computeForcePositionJacobian(Matrix3d M)

Computes the force/position Jacobian of this spring. This gives the change in the force acting on the first point with respect to a change in the position of the first point.

Parameters:

M - matrix in which to return the result

computeForceVelocityJacobian

public void computeForceVelocityJacobian(Matrix3d M)

Computes the force/velocity Jacobian of this spring. This gives the change in the force acting on the first point with respect to a change in the velocity of the first point.

Parameters:

M - matrix in which to return the result

addSolveBlocks

public void addSolveBlocks(SparseNumberedBlockMatrix M)

Description copied from interface: ForceEffector

Adds any needed blocks to a solve matrix in order to accomodate the Jacobian terms associated with this force effector. In general, blocks will be need to be added at locations given by the block indices (bi, bj), where bi and bj correspond to the solve indices (as returned by getSolveIndex) for all dynamic or attached components affected by this force effector.

Specified by:

addSolveBlocks in interface ForceEffector

Parameters:

M - solve matrix to which blocks should be added

addPosJacobian

public void addPosJacobian(SparseNumberedBlockMatrix M,
                           double s)

Description copied from interface: ForceEffector

Scales the components of the position Jacobian associated with this force effector and adds it to the supplied solve matrix M.

M is guaranteed to be the same matrix supplied in the most recent call to addSolveBlocks, and so implementations may choose to cache the relevant matrix blocks from that call, instead of retrieving them directly from M.

Specified by:

addPosJacobian in interface ForceEffector

Parameters:

M - solve matrix to which scaled position Jacobian is to be added

s - scaling factor for position Jacobian

addVelJacobian

public void addVelJacobian(SparseNumberedBlockMatrix M,
                           double s)

Description copied from interface: ForceEffector

Scales the components of the velocity Jacobian associated with this force effector and adds it to the supplied solve matrix M.

M is guaranteed to be the same matrix supplied in the most recent call to addSolveBlocks, and so implementations may choose to cache the relevant matrix blocks from that call, instead of retrieving them directly from M.

Specified by:

addVelJacobian in interface ForceEffector

Parameters:

M - solve matrix to which scaled velocity Jacobian is to be added

s - scaling factor for velocity Jacobian

getForceSize

public int getForceSize()

Specified by:

getForceSize in interface ForceTargetComponent

getForce

public void getForce(VectorNd minf,
                     boolean staticOnly)

Specified by:

getForce in interface ForceTargetComponent

addForcePosJacobian

public int addForcePosJacobian(SparseBlockMatrix J,
                               double h,
                               boolean staticOnly,
                               int bi)

Description copied from interface: ForceTargetComponent

Add a row to the force Jacobian for this force target component. The Jacobian maps state velocities u into the forces fm that should be minimized

 fm = J u
 

Specified by:

addForcePosJacobian in interface ForceTargetComponent

Parameters:

J - force Jacobian

h - current time step

staticOnly - use only static forces

bi - block row index for the row to be added

Returns:

bi + 1

addForceVelJacobian

public int addForceVelJacobian(SparseBlockMatrix J,
                               double h,
                               int bi)

Specified by:

addForceVelJacobian in interface ForceTargetComponent

getJacobianType

public int getJacobianType()

Description copied from interface: ForceEffector

Returns a code indicating the matrix type that results when the Jacobian terms of this force effector are added to the solve matrix. This should be a logical or-ing of either Matrix.SYMMETRIC or Matrix.POSITIVE_DEFINITE. The former should be set if adding the Jacobian terms preserves symmetry, and the latter should be set if positive definiteness if preserved. Both should be set if there is no Jacobian for this effector (i.e., the Jacobian methods are not implemented). Matrix types from all the force effectors are logically and-ed together to determine the type for the entire solve matrix.

Specified by:

getJacobianType in interface ForceEffector

Returns:

solve matrix type resulting from adding Jacobian terms

isDuplicatable

public boolean isDuplicatable()

Returns true if this component can be duplicated. Duplication means that we can expect to be able to make a complete copy of the component along with all it's external references. This method should return true if and only if CopyableComponent.getCopyReferences(java.util.List<artisynth.core.modelbase.ModelComponent>, artisynth.core.modelbase.ModelComponent) returns true.

This method is not currently used. It is intended to provide a faster way of determining if a component can be duplicated, without having to use CopyableComponent.getCopyReferences(java.util.List<artisynth.core.modelbase.ModelComponent>, artisynth.core.modelbase.ModelComponent) to build the list of copy references.

Specified by:

isDuplicatable in interface CopyableComponent

Returns:

true if this component can be duplicated.

getCopyReferences

public boolean getCopyReferences(java.util.List<ModelComponent> refs,
                                 ModelComponent ancestor)

Collects external references which must also be copied in order to duplicate this component. These references should exclude those which are contained within a specified component hierarchy. This method should return true if and only if CopyableComponent.isDuplicatable() returns true.

Specified by:

getCopyReferences in interface CopyableComponent

Parameters:

refs - list to which references are appended

ancestor - root node of the hierarchy from which references are to be excluded

Returns:

false if it is discovered that the component cannot be duplicated

copy

public ModelComponent copy(int flags,
                           java.util.Map<ModelComponent,ModelComponent> copyMap)

Description copied from interface: CopyableComponent

Create a copy of this component. If COPY_REFERENCES is set in flags, then any component referenced by this component should itself be set to a copy. This should be done first checking copyMap for an existing copy of the referenced component. If there is no existing copy, then a copy should be created by calling copy recursively and adding the new copy to copyMap.

Specified by:

copy in interface CopyableComponent

Overrides:

copy in class PointSpringBase

Parameters:

flags - flags to control the copying

copyMap - map to possible existing instances of referenced components

Returns:

copy of this component

getHardReferences

public void getHardReferences(java.util.List<ModelComponent> refs)

Description copied from class: ModelComponentBase

Appends all hard references for this component to a list. References are other components, outside of this component's immediate ancestry, on which this component depends. For example, an AxialSpring refers to two Point components as for it's end points. A hard reference is one which the referring component must have, and which if deleted, implies that the referring component should be deleted too.

Specified by:

getHardReferences in interface ModelComponent

Overrides:

getHardReferences in class ModelComponentBase

Parameters:

refs - list to which hard references are appended