PointSpringBase (Artisynth API documentation)

java.lang.Object
- artisynth.core.modelbase.ModelComponentBase
- - artisynth.core.mechmodels.Spring
  - - artisynth.core.mechmodels.PointSpringBase

All Implemented Interfaces:

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

Direct Known Subclasses:

AxialSpring, MultiPointSpring
```
public abstract class PointSpringBase
extends Spring
implements RenderableComponent, ScalableUnits, HasNumericState
```
Base class for springs based on two or more points

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 boolean myIgnoreCoriolisInJacobian

static PropertyList myProps

static boolean useMaterial
- Fields inherited from class artisynth.core.modelbase.ModelComponentBase
  enforceUniqueCompositeNames, enforceUniqueNames, myNumber, NULL_OBJ, useCompactPathNames
- Fields inherited from interface maspack.render.IsRenderable
  TRANSPARENT, TWO_DIMENSIONAL

Fields
Modifier and Type	Field and Description
`static boolean`	`myIgnoreCoriolisInJacobian`
`static PropertyList`	`myProps`
`static boolean`	`useMaterial`

Constructor Summary

Constructors
Constructor and Description

PointSpringBase(java.lang.String name)

Constructors
Constructor and Description
`PointSpringBase(java.lang.String name)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`advanceState(double t0, double t1)` If `HasNumericState.requiresAdvance()` and `HasNumericState.hasState()` both return `true`, then this method is called each time step by the system integrator to update this component's state.
`double`	`computeDFdl(double l, double ldot)` Computes the derivative of the tension F (acting along the unit vector from the first to the second particle) with respect to spring length.
`double`	`computeDFdl(double l, double ldot, double ex)` Computes the derivative of the tension F (acting along the unit vector from the first to the second particle) with respect to spring length.
`double`	`computeDFdldot(double l, double ldot)` Computes the derivative of the tension F (acting along the unit vector from the first to the second particle)with respect to the time derivative of spring length.
`double`	`computeDFdldot(double l, double ldot, double ex)` Computes the derivative of the tension F (acting along the unit vector from the first to the second particle)with respect to the time derivative of spring length.
`double`	`computeF(double l, double ldot)` Computes the tension F acting along the unit vector from the first to the second particle.
`double`	`computeF(double l, double ldot, double ex)` Computes the tension F acting along the unit vector from the first to the second particle.
`boolean`	`containsPoint(Point pnt)` Queries whether this spring contains a specified point.
`ModelComponent`	`copy(int flags, java.util.Map<ModelComponent,ModelComponent> copyMap)`
`static AxialMaterial`	`createDefaultMaterial()`
`RenderProps`	`createRenderProps()` Factory method to create render properties appropriate to this object.
`PropertyList`	`getAllPropertyInfo()` Returns a list giving static information about all properties exported by this object.
`int`	`getAuxVarDerivative(double[] buf, int idx)` If this component has auxiliary variables, returns the current values of their derivatives in `buf`, starting at the location `idx`.
`int`	`getAuxVarState(double[] buf, int idx)` If this component has auxiliary variables, returns their values in `buf`, starting at the location `idx`.
`AxialMaterial`	`getEffectiveMaterial()`
`double`	`getForceScaling()` Special method that checks if the material is an instance of AxialMuscleMaterial, and if it is, returns the forceScaling of that material.
`abstract double`	`getLength()`
`abstract double`	`getLengthDot()`
`AxialMaterial`	`getMaterial()`
`static double`	`getMaxForce(PointSpringBase s)`
`abstract Point`	`getPoint(int idx)` Returns the `idx`-th point in this spring.
`float[]`	`getRenderColor()`
`int`	`getRenderHints()` Returns a bit code giving rendering hints about this renderable.
`RenderProps`	`getRenderProps()` Returns the render properities for this object.
`double`	`getRestLength()`
`void`	`getSelection(java.util.LinkedList<java.lang.Object> list, int qid)` Append to `list` the component (or components) associated with the `qid`-th selection query issued by this component's render method.
`void`	`getState(DataBuffer data)` Saves state information for this component by adding data to the supplied DataBuffer.
`int`	`getStateVersion()` Returns a version number for this component's state.
`boolean`	`hasState()` Queries if this component has state.
`abstract int`	`indexOfPoint(Point pnt)` Returns the index of a specified point in this spring, or -1 if the point is not present.
`boolean`	`isSelectable()` Returns true if this object is in fact selectable.
`void`	`normalizeForceScaling()` Special method that checks if the material is an instance of AxialMuscleMaterial, and if it is, sets the forceScaling to 1 and adjusts the maxforce and damping accordingly.
`int`	`numAuxVars()` Returns the number of auxiliary variables associated with this component, or 0 if there are no auxiliary variables.
`abstract int`	`numPoints()` Queries the number of points in this spring.
`int`	`numSelectionQueriesNeeded()` If this selectable manages its own selection (by issuing selection queries within its `render` method), then this method should return the maximum number of selection queries that will be required.
`void`	`prerender(RenderList list)` Called prior to rendering to allow this object to update the internal state required for rendering (such as by caching rendering coordinates).
`abstract void`	`render(Renderer renderer, int flags)` Render this object using the functionality of the supplied `Renderer`.
`boolean`	`requiresAdvance()` Returns `true` if the state of this component must be updated each time step using `HasNumericState.advanceState(double, double)`.
`void`	`scaleDistance(double s)` Scales all distance coordinates.
`void`	`scaleMass(double s)` Scales all mass units.
`int`	`setAuxVarState(double[] buf, int idx)` If this component has auxiliary variables, sets them from the values in `buf`, starting at the location `idx`.
`static void`	`setDamping(PointSpringBase s, double d)`
`void`	`setLinearMaterial(double k, double d)`
`<T extends AxialMaterial> void`	`setMaterial(T mat)`
`static void`	`setMaxForce(PointSpringBase s, double maxf)`
`abstract void`	`setPoint(int idx, Point pnt)` Sets a point at a particular index.
`void`	`setRenderProps(RenderProps props)` Assigns a new set of render properties to this object.
`void`	`setRestLength(double l)`
`abstract double`	`setRestLengthFromPoints()` Sets the rest length of the spring from the current point locations
`void`	`setState(DataBuffer data)` Restores the state for this component by reading from the supplied data buffer, starting at the current buffer offsets.
`static void`	`setStiffness(PointSpringBase s, double k)`
`abstract void`	`updateBounds(Vector3d pmin, Vector3d pmax)` Update the minimum and maximum points for this object.

Methods inherited from class artisynth.core.mechmodels.Spring
applyForces

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, getHardReferences, getName, getNavpanelVisibility, getNumber, getParent, getSoftReferences, 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, write

Methods inherited from interface artisynth.core.mechmodels.ForceEffector
addPosJacobian, addSolveBlocks, addVelJacobian, getJacobianType

- Field Detail
  - myIgnoreCoriolisInJacobian
```
public static boolean myIgnoreCoriolisInJacobian
```
  - useMaterial
```
public static boolean useMaterial
```
  - myProps
```
public static PropertyList myProps
```
- Constructor Detail
  - PointSpringBase
```
public PointSpringBase(java.lang.String name)
```
- 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 ModelComponentBase
    
    Returns:
    
    static information for all exported properties
  - numPoints
```
public abstract int numPoints()
```
    Queries the number of points in this spring.
    
    Returns:
    
    number of points in the spring
  - getPoint
```
public abstract Point getPoint(int idx)
```
    Returns the idx-th point in this spring.
    
    Parameters:
    
    idx - point index
    
    Returns:
    
    the idx-th point
  - setPoint
```
public abstract void setPoint(int idx,
                              Point pnt)
```
    Sets a point at a particular index. The index must be < numPoints().
    
    Parameters:
    
    idx - specifies point position
    
    pnt - replacement point
  - indexOfPoint
```
public abstract int indexOfPoint(Point pnt)
```
    Returns the index of a specified point in this spring, or -1 if the point is not present.
    
    Parameters:
    
    pnt - point whose index is desired
    
    Returns:
    
    index of the point, or -1 if not present
  - containsPoint
```
public boolean containsPoint(Point pnt)
```
    Queries whether this spring contains a specified point.
    
    Returns:
    
    true if the spring contains the point
  - createDefaultMaterial
```
public static AxialMaterial createDefaultMaterial()
```
  - getMaterial
```
public AxialMaterial getMaterial()
```
  - getForceScaling
```
public double getForceScaling()
```
    Special method that checks if the material is an instance of AxialMuscleMaterial, and if it is, returns the forceScaling of that material. Used to try and eliminate the use of forceScaling.
  - normalizeForceScaling
```
public void normalizeForceScaling()
```
    Special method that checks if the material is an instance of AxialMuscleMaterial, and if it is, sets the forceScaling to 1 and adjusts the maxforce and damping accordingly.
  - setLinearMaterial
```
public void setLinearMaterial(double k,
                              double d)
```
  - setMaterial
```
public <T extends AxialMaterial> void setMaterial(T mat)
```
  - getEffectiveMaterial
```
public AxialMaterial getEffectiveMaterial()
```
  - getLength
```
public abstract double getLength()
```
  - getLengthDot
```
public abstract double getLengthDot()
```
  - setRestLengthFromPoints
```
public abstract double setRestLengthFromPoints()
```
    Sets the rest length of the spring from the current point locations
    
    Returns:
    
    the new rest length
  - getRestLength
```
public double getRestLength()
```
  - setRestLength
```
public void setRestLength(double l)
```
  - getRenderProps
```
public RenderProps getRenderProps()
```
    Description copied from interface: HasRenderProps
    
    Returns the render properities for this object. If no render properties are assigned, this routines returns null.
    
    Specified by:
    
    getRenderProps in interface HasRenderProps
    
    Returns:
    
    current render properties for this object
  - setRenderProps
```
public void setRenderProps(RenderProps props)
```
    Description copied from interface: HasRenderProps
    
    Assigns a new set of render properties to this object. An argument of null will remove render properties from this object.
    
    Specified by:
    
    setRenderProps in interface HasRenderProps
    
    Parameters:
    
    props - new render properties for this object
  - createRenderProps
```
public RenderProps createRenderProps()
```
    Description copied from interface: HasRenderProps
    
    Factory method to create render properties appropriate to this object.
    
    Specified by:
    
    createRenderProps in interface HasRenderProps
    
    Returns:
    
    new render properties for this object
  - prerender
```
public void prerender(RenderList list)
```
    Description copied from interface: IsRenderable
    
    Called prior to rendering to allow this object to update the internal state required for rendering (such as by caching rendering coordinates). The object may add internal objects to the list of objects being rendered, by calling
    list.addIfVisible (obj);
    for each of the objects in question.
    
    Specified by:
    
    prerender in interface IsRenderable
    
    Parameters:
    
    list - list of objects to be rendered
  - updateBounds
```
public abstract 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
    
    Parameters:
    
    pmin - minimum point
    
    pmax - maximum point
  - getRenderHints
```
public int getRenderHints()
```
    Description copied from interface: IsRenderable
    
    Returns a bit code giving rendering hints about this renderable. Current bit codes include TRANSPARENT and TWO_DIMENSIONAL.
    
    Specified by:
    
    getRenderHints in interface IsRenderable
    
    Returns:
    
    bit code of rendering hints.
  - isSelectable
```
public boolean isSelectable()
```
    Description copied from interface: IsSelectable
    
    Returns true if this object is in fact selectable.
    
    Specified by:
    
    isSelectable in interface IsSelectable
    
    Returns:
    
    true if this object is selectable
  - numSelectionQueriesNeeded
```
public int numSelectionQueriesNeeded()
```
    Description copied from interface: IsSelectable
    
    If this selectable manages its own selection (by issuing selection queries within its render method), then this method should return the maximum number of selection queries that will be required. Otherwise, this method should return -1.
    
    Specified by:
    
    numSelectionQueriesNeeded in interface IsSelectable
    
    Returns:
    
    maximum number of selection queries needed by this component, or -1 if this component does not manage its own selection.
  - render
```
public abstract 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
    
    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.
  - getSelection
```
public void getSelection(java.util.LinkedList<java.lang.Object> list,
                         int qid)
```
    Description copied from interface: IsSelectable
    
    Append to list the component (or components) associated with the qid-th selection query issued by this component's render method. This will only be called if this component manages its own selection (i.e., the number nums returned by IsSelectable.numSelectionQueriesNeeded() is positive), and qid will in turn be a number between 0 and nums-1.
    
    Specified by:
    
    getSelection in interface IsSelectable
    
    Parameters:
    
    list - selected objects are appended to the end of this list
    
    qid - index of the selection query
  - computeF
```
public double computeF(double l,
                       double ldot)
```
    Computes the tension F acting along the unit vector from the first to the second particle.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    Returns:
    
    force tension
  - computeF
```
public double computeF(double l,
                       double ldot,
                       double ex)
```
    Computes the tension F acting along the unit vector from the first to the second particle.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    ex - excitation applied to the muscle material
    
    Returns:
    
    force tension
  - computeDFdl
```
public double computeDFdl(double l,
                          double ldot)
```
    Computes the derivative of the tension F (acting along the unit vector from the first to the second particle) with respect to spring length.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    Returns:
    
    force tension derivative with respect to length
  - computeDFdl
```
public double computeDFdl(double l,
                          double ldot,
                          double ex)
```
    Computes the derivative of the tension F (acting along the unit vector from the first to the second particle) with respect to spring length.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    ex - excitation applied to the muscle material
    
    Returns:
    
    force tension derivative with respect to length
  - computeDFdldot
```
public double computeDFdldot(double l,
                             double ldot)
```
    Computes the derivative of the tension F (acting along the unit vector from the first to the second particle)with respect to the time derivative of spring length.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    Returns:
    
    force tension derivative with respect to length time derivative
  - computeDFdldot
```
public double computeDFdldot(double l,
                             double ldot,
                             double ex)
```
    Computes the derivative of the tension F (acting along the unit vector from the first to the second particle)with respect to the time derivative of spring length.
    
    Parameters:
    
    l - spring length
    
    ldot - spring length derivative
    
    ex - excitation applied to the muscle material
    
    Returns:
    
    force tension derivative with respect to length time derivative
  - getRenderColor
```
public float[] getRenderColor()
```
  - scaleDistance
```
public void scaleDistance(double s)
```
    Description copied from interface: ScalableUnits
    
    Scales all distance coordinates.
    
    Specified by:
    
    scaleDistance in interface ScalableUnits
    
    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
    
    Parameters:
    
    s - scaling factor
  - setStiffness
```
public static void setStiffness(PointSpringBase s,
                                double k)
```
  - setDamping
```
public static void setDamping(PointSpringBase s,
                              double d)
```
  - setMaxForce
```
public static void setMaxForce(PointSpringBase s,
                               double maxf)
```
  - getMaxForce
```
public static double getMaxForce(PointSpringBase s)
```
  - hasState
```
public boolean hasState()
```
    Queries if this component has state. Structure change events involving components that have state will cause the current state history of of the system to be cleared.
    
    Specified by:
    
    hasState in interface HasNumericState
    
    Specified by:
    
    hasState in interface ModelComponent
    
    Overrides:
    
    hasState in class ModelComponentBase
    
    Returns:
    
    true if this component has state
  - getStateVersion
```
public int getStateVersion()
```
    Returns a version number for this component's state. When the version number changes, any previously saved state should be considered no longer compatible. The default implementation of this method always returns 0, indicating that state compatibility never changes.
    
    Specified by:
    
    getStateVersion in interface HasNumericState
  - getState
```
public void getState(DataBuffer data)
```
    Saves state information for this component by adding data to the supplied DataBuffer. Existing data in the buffer should not be disturbed.
    
    Specified by:
    
    getState in interface HasNumericState
    
    Parameters:
    
    data - buffer for storing the state values.
  - setState
```
public void setState(DataBuffer data)
```
    Restores the state for this component by reading from the supplied data buffer, starting at the current buffer offsets.
    
    Specified by:
    
    setState in interface HasNumericState
    
    Parameters:
    
    data - buffer containing the state information
  - requiresAdvance
```
public boolean requiresAdvance()
```
    Returns true if the state of this component must be updated each time step using HasNumericState.advanceState(double, double).
    
    Specified by:
    
    requiresAdvance in interface HasNumericState
    
    Returns:
    
    true if advanceState must be called
  - advanceState
```
public void advanceState(double t0,
                         double t1)
```
    If HasNumericState.requiresAdvance() and HasNumericState.hasState() both return true, then this method is called each time step by the system integrator to update this component's state. For single step integrators, the method is called once at the start of the integration, with t0 and t1 set to the step's start and end times. For multi-step integrators (such as Runge Kutta), the method is called for each sub-step, with t0 and t1 set to the sub-step's time bounds. Multi-step integrators will also use HasNumericState.getState(maspack.util.DataBuffer) and HasNumericState.setState(maspack.util.DataBuffer) to save and restore state as required.
    
    Specified by:
    
    advanceState in interface HasNumericState
    
    Parameters:
    
    t0 - beginning time associated with the time step or sub-step
    
    t1 - end time associated with the time step or sub-step
  - numAuxVars
```
public int numAuxVars()
```
    Returns the number of auxiliary variables associated with this component, or 0 if there are no auxiliary variables.
    If HasNumericState.hasState() returns true and the component has auxiliary variables, the variables are updated each time step by the system integrator using explcit integration of the form
```
 w += h dwdt
 
```
    where h is a time increment, w is a vector of variables accessed using HasNumericState.getAuxVarState(double[], int) and HasNumericState.setAuxVarState(double[], int), and dwdt is a time derivative obtained using HasNumericState.getAuxVarDerivative(double[], int). For single step integrators, this will be done once at the start of the integration, with h set to the time step size. For multi-step integrators (such as Runge Kutta), this will be done at the start of each sub-step, with h set to the sub-step size.
    If present, auxiliary variables are also assumed to be contained within the state accessed using HasNumericState.getState(maspack.util.DataBuffer) and HasNumericState.setState(maspack.util.DataBuffer).
    Specified by:
    
    numAuxVars in interface HasNumericState
    
    Returns:
    
    number of auxiliary variables.
  - getAuxVarState
```
public int getAuxVarState(double[] buf,
                          int idx)
```
    If this component has auxiliary variables, returns their values in buf, starting at the location idx. See HasNumericState.numAuxVars() for a description of auxiliary variables. The method returns idx + num, where num is the number of variables.
    
    Specified by:
    
    getAuxVarState in interface HasNumericState
    
    Parameters:
    
    buf - returns the variable values
    
    idx - starting point within buf
    
    Returns:
    
    idx plus the number of variables
  - setAuxVarState
```
public int setAuxVarState(double[] buf,
                          int idx)
```
    If this component has auxiliary variables, sets them from the values in buf, starting at the location idx. See HasNumericState.numAuxVars() for a description of auxiliary variables. The method returns idx + num, where num is the number of variables.
    
    Specified by:
    
    setAuxVarState in interface HasNumericState
    
    Parameters:
    
    buf - contains the new variable values
    
    idx - starting point within buf
    
    Returns:
    
    idx plus the number of variables
  - getAuxVarDerivative
```
public int getAuxVarDerivative(double[] buf,
                               int idx)
```
    If this component has auxiliary variables, returns the current values of their derivatives in buf, starting at the location idx. See HasNumericState.numAuxVars() for a description of auxiliary variables. The method returns idx + num, where num is the number of variables.
    
    Specified by:
    
    getAuxVarDerivative in interface HasNumericState
    
    Parameters:
    
    buf - returns the variable derivative values
    
    idx - starting point within buf
    
    Returns:
    
    idx plus the number of variables
  - copy
```
public ModelComponent copy(int flags,
                           java.util.Map<ModelComponent,ModelComponent> copyMap)
```
    Overrides:
    
    copy in class ModelComponentBase

Class PointSpringBase

Nested Class Summary

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

Field Summary

Fields inherited from class artisynth.core.modelbase.ModelComponentBase

Fields inherited from interface maspack.render.IsRenderable

Constructor Summary

Method Summary

Methods inherited from class artisynth.core.mechmodels.Spring

Methods inherited from class artisynth.core.modelbase.ModelComponentBase

Methods inherited from class java.lang.Object

Methods inherited from interface artisynth.core.modelbase.ModelComponent

Methods inherited from interface maspack.properties.HasProperties

Methods inherited from interface maspack.properties.HierarchyNode

Methods inherited from interface artisynth.core.modelbase.PostScannable

Methods inherited from interface maspack.util.Scannable

Methods inherited from interface artisynth.core.mechmodels.ForceEffector

Field Detail

myIgnoreCoriolisInJacobian

useMaterial

myProps

Constructor Detail

PointSpringBase

Method Detail

getAllPropertyInfo

numPoints

getPoint

setPoint

indexOfPoint

containsPoint

createDefaultMaterial

getMaterial

getForceScaling

normalizeForceScaling

setLinearMaterial

setMaterial

getEffectiveMaterial

getLength

getLengthDot

setRestLengthFromPoints

getRestLength

setRestLength

getRenderProps

setRenderProps

createRenderProps

prerender

updateBounds

getRenderHints

isSelectable

numSelectionQueriesNeeded

render

getSelection

computeF

computeF

computeDFdl

computeDFdl

computeDFdldot

computeDFdldot

getRenderColor

scaleDistance

scaleMass

setStiffness

setDamping

setMaxForce

getMaxForce

hasState

getStateVersion

getState

setState

requiresAdvance

advanceState

numAuxVars

getAuxVarState

setAuxVarState

getAuxVarDerivative

copy