artisynth.core.femmodels

Class FemElement3d

java.lang.Object

artisynth.core.modelbase.ModelComponentBase

artisynth.core.modelbase.RenderableComponentBase

artisynth.core.femmodels.FemElement

artisynth.core.femmodels.FemElement3dBase

artisynth.core.femmodels.FemElement3d

All Implemented Interfaces:

FrameAttachable, PointAttachable, CopyableComponent, HasNumericState, ModelComponent, PostScannable, PropertyChangeListener, RenderableComponent, ScalableUnits, java.lang.Cloneable, Boundable, HasProperties, HierarchyNode, HasRenderProps, IsRenderable, IsSelectable, Renderable, Scannable

Direct Known Subclasses:

BSpline3dElement, HexElement, MFreeElement3d, PyramidElement, QuadhexElement, QuadpyramidElement, QuadtetElement, QuadwedgeElement, TetElement, WedgeElement

public abstract class FemElement3d
extends FemElement3dBase

Nested Class Summary

Nested classes/interfaces inherited from class artisynth.core.femmodels.FemElement

FemElement.ElementClass

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

ModelComponent.NavpanelVisibility

Field Summary

Fields inherited from class artisynth.core.femmodels.FemElement3dBase

myProps

Fields inherited from class artisynth.core.femmodels.FemElement

setScannedNodesInPostscan, writeNodeRefsByNumber

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
FemElement3d()

Method Summary

Modifier and Type	Method and Description
void	computeJacobian(Matrix3d J, Vector3d ncoords)
void	computeLocalPosition(Vector3d pnt, Vector3d ncoords) Compute position within element based on natural coordinates
double	computeRestVolumes() Computes the rest volume associated with this element and stores the result in the myRestVolume field.
double	computeVolumes() Computes the volume associated with this element and stores the result in the myVolume field.
FemElement3d	copy(int flags, java.util.Map<ModelComponent,ModelComponent> copyMap) Create a copy of this component.
static FemElement3d	createElement(FemNode3d[] nodes)
static FemElement3d	createElement(FemNode3d[] nodes, boolean flipped)
double	getH(int i, Vector3d coords) Returns the value of the pressure shape function.
MatrixBlock[]	getIncompressConstraints() Returns an array of MatrixBlocks to be used as constraints to make the element incompressible.
int	getIncompressIndex()
double[]	getLagrangePressures() Lagrange pressures array for use with incompressibility
Matrix	getPressureWeightMatrix() Returns the pressure weight matrix for this element.
double[]	getRestVolumes() Returns the partial rest volumes.
double[]	getVolumes() Returns the partial volumes.
int	numPressureVals() Returns the number of pressure variables associated with this element.
void	scaleDistance(double s) Scales all distance coordinates.
void	setIncompressIndex(int idx)

Methods inherited from class artisynth.core.femmodels.FemElement3dBase

addConsistentGravity, addConsistentMass, advanceState, clearRotationData, computeConsistentMass, computeCovariance, computeDirectedRenderSize, computeGravityWeights, computeRenderCoordsAndGradient, connectToHierarchy, containsEdge, containsFace, containsFace, containsNode, coordsAreInside, createFrameAttachment, createIntegrationPoints, createPointAttachment, disconnectFromHierarchy, getAllIntegrationPoints, getAllPropertyInfo, getCopyReferences, getDeformation, getDeformation, getdNds, getEdgeIndices, getElementClass, getElementWidgetSize, getElementWidgetSizeMode, getFaceIndices, getFaces, getFemModel, getFrame, getIntegrationCoords, getIntegrationData, getIntegrationPoints, getIntegrationShapeMatrix, getInvB, getInvB, getMarkerCoordinates, getN, getNaturalCoordinates, getNaturalCoordinates, getNaturalCoordinatesGSS, getNodalAveragingMatrix, getNodalExtrapolationMatrix, getNodeCoords, getNodeCoords, getNodeMassWeights, getNodeNeighbors, getNodes, getNumFaces, getRotation, getRotation, getState, getStiffnessWarper, getTriangulatedFaceIndices, getWarpingData, getWarpingPoint, invalidateRestData, invalidateRotationData, isInside, isInvertedAtRest, notifyStateVersionChanged, numAllIntegrationPoints, numIntegrationPoints, renderWidget, requiresAdvance, setElementWidgetSize, setElementWidgetSizeMode, setFrame, setNodes, setState, setStiffnessWarper, triangulateFace

Methods inherited from class artisynth.core.femmodels.FemElement

addAugmentingMaterial, addAuxiliaryMaterial, computeCentroid, containsNode, createRenderProps, defaultRenderPropsAreNull, getAugmentingMaterials, getAuxiliaryMaterials, getDensity, getDensityMode, getEffectiveMaterial, getHardReferences, getIndex, getLocalNodeIndex, getMass, getMaterial, getPlasticDeformation, getPoint, getRestVolume, getSelection, getStateVersion, getStrainEnergy, getVolume, hasActiveNodes, hasControllableNodes, hasState, integrationPointsInterpolateToNodes, integrationPointsMapToNodes, invalidateMassIfNecessary, isDuplicatable, isInverted, isLinear, isMassExplicit, materialsAreInvertible, numAugmentingMaterials, numAuxiliaryMaterials, numberString, numNodes, numPoints, prerender, propertyChanged, removeAugmentingMaterial, removeAuxiliaryMaterial, render, render, scaleMass, setDensity, setDensityMode, setExplicitMass, setIndex, setInverted, setMass, setMaterial, setPlasticDeformation, unsetExplicitMass, updateBounds, updateRestVolumeAndMass

Methods inherited from class artisynth.core.modelbase.RenderableComponentBase

getRenderHints, getRenderProps, isSelectable, isVisible, numSelectionQueriesNeeded, setRenderProps, setVisible, updateRenderProps

Methods inherited from class artisynth.core.modelbase.ModelComponentBase

checkFlag, checkName, checkNameUniqueness, clearFlag, clone, createTempFlag, 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, write

Methods inherited from class java.lang.Object

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

Methods inherited from interface artisynth.core.modelbase.ModelComponent

getHardReferences, 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, write

Methods inherited from interface artisynth.core.modelbase.HasNumericState

getAuxVarDerivative, getAuxVarState, numAuxVars, setAuxVarState

Constructor Detail

FemElement3d

public FemElement3d()

Method Detail

computeVolumes

public double computeVolumes()

Computes the volume associated with this element and stores the result in the myVolume field.

The method should return the minimum Jacobian determinant ratio (det(J)/det(J0)) over all integration points. A negative value indicates that the element is "inverted" at one or more integration points.

Partial volumes are also computed, and stored in the myVolumes field. If the number of pressure values is 1, then there is only one partial volume which is equal to the overall volume.

The base implementation of this method used quadrature.Individual elements can override this with a more efficient method if needed.

Specified by:

computeVolumes in class FemElement

Returns:

minimum Jacobian determinant ratio

getVolumes

public double[] getVolumes()

Returns the partial volumes. The number of partial volumes is equals to the number of pressure values.

Returns:

current partial volumes

computeRestVolumes

public double computeRestVolumes()

Computes the rest volume associated with this element and stores the result in the myRestVolume field.

The method should return the minimum Jacobian determinant (det(J0)) over all integration points. A negative value indicates that the element is "inverted" in its rest position at one or more integration points.

Partial rest volumes are also computed, and stored in the myRestVolumes field. If the number of pressure values is 1, then there is only one partial rest volume which is equal to the overall rest volume.

The base implementation of this method used quadrature. Individual elements can override this with a more efficient method if needed.

Specified by:

computeRestVolumes in class FemElement

Returns:

minimum Jacobian determinant

getRestVolumes

public double[] getRestVolumes()

Returns the partial rest volumes. The number of partial rest volumes is equals to the number of pressure values.

Returns:

current partial rest volumes

getIncompressIndex

public int getIncompressIndex()

setIncompressIndex

public void setIncompressIndex(int idx)

numPressureVals

public int numPressureVals()

Returns the number of pressure variables associated with this element. All of the linear elements have one pressure variable, whereas some of the quadratic elements have more.

Returns:

number of pressure variables.make

getH

public double getH(int i,
                   Vector3d coords)

Returns the value of the pressure shape function. By default, this method returns 1, corresponding to a single pressure variable with constant value over the entire element. Elements with a larger number of pressure DOFs should override this method to supply the appropriate shape functions.

Parameters:

i - index of the pressure variable; should be less than the value returned by numPressureVals()

coords - coordinates at which the shape function should be evaluated.

Returns:

value of the pressure shape function

getPressureWeightMatrix

public Matrix getPressureWeightMatrix()

Returns the pressure weight matrix for this element. The pressure weight matrix is given by the inverse of the integral of H^T H, where H is the row vector formed from the pressure shape functions.

By default, this method returns a pressure weight matrix for the case where there is only one pressure value. Such matrices always have a single value of 1. Elements with a larger number of pressure values should override this method to return a pressure weight matrix appropriate for that element.

Returns:

pressure weight matrix for this element

getIncompressConstraints

public MatrixBlock[] getIncompressConstraints()

Returns an array of MatrixBlocks to be used as constraints to make the element incompressible. Note this method does not compute values for these constraints; it only returns storage for them.

There is one block for each node, with each of size 3 x m, where m is the number of pressure degrees-of-freedom (returned by numPressureVals().

Returns:

incompressibility constraints

computeLocalPosition

public void computeLocalPosition(Vector3d pnt,
                                 Vector3d ncoords)

Compute position within element based on natural coordinates

Specified by:

computeLocalPosition in class FemElement3dBase

Parameters:

pnt - position within element

ncoords - natural coordinates

computeJacobian

public void computeJacobian(Matrix3d J,
                            Vector3d ncoords)

Specified by:

computeJacobian in class FemElement3dBase

getLagrangePressures

public double[] getLagrangePressures()

Lagrange pressures array for use with incompressibility

Returns:

pressures

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 FemElement

Parameters:

s - scaling factor

copy

public FemElement3d 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 FemElement3dBase

Parameters:

flags - flags to control the copying

copyMap - map to possible existing instances of referenced components

Returns:

copy of this component

createElement

public static FemElement3d createElement(FemNode3d[] nodes)

createElement

public static FemElement3d createElement(FemNode3d[] nodes,
                                         boolean flipped)