spring

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        The spring node represents a group of springs between points in one or more
        particle or geometry objects.  The stiffness, damping, restLength, and
        end1weight/end2Weight attributes control the motion of the springs.

rigidConstraint, dynBase, field, airField, turbulenceField, radialField, vortexField, newtonField, volumeAxisField, dragField, uniformField, gravityField, pointEmitter, particle, rigidBody, geoConnectable

count, damping, dampingPS, deltaTime, end1Weight, end2Weight, idIndex, idMapping, lengths, manageParticleDeath, maxUsed, minSprings, minUsed, obj0Index, obj1Index, objCount, object0, object1, objectMass, objectPositions, objectVelocities, objects, outputForce, point0, point1, pt0Index, pt1Index, restLength, restLengthPS, sortedId, stiffness, stiffnessPS, useDampingPS, useRestLengthPS, useStiffnessPS, validIndex

Long name (short name)	Type	Default	Flags
end1Weight (f)	double	1
The amount [0,1] that the first or the 'from' end will be affected by the spring.
end2Weight (t)	double	1
The amount [0,1] that the second or the 'to' end will be affected by the spring.
useStiffnessPS (usps)	bool	true
This attribute determines if the node uses per object or per spring stiffness. If true, each spring will use the corresponding value in the stiffnessPS array. If false, every spring will use the stiffness attribute value.
useDampingPS (udps)	bool	true
This attribute determines if the node uses per object or per spring damping. If true, each spring will use the corresponding value in the dampingPS array. Otherwise, every spring will use the damping attribute value.
useRestLengthPS (urps)	bool	true
This attribute determines if the node uses per object or per spring rest length. If true, each spring will use the corresponding value in the restLengthPS array. Otherwise, every spring will use the restLength attribute value.
stiffness (s)	double	1
This attribute is per object. The strength with which springs are trying to maintain their length.
damping (d)	double	.2
This attribute is per object. How strongly the motion of springs are damped by the 'physical' properties of the springs. A larger value makes the springs converge faster to their rest length.
restLength (r)	double	0
This attribute is per object. The length at which springs try to stay.
stiffnessPS (sps)	doubleArray	empty
This attribute is per spring. The strength with which springs are trying to maintain their length. PS stands for per-spring. This attribute stores an array of data, one for each spring. The value can be edited with the spring command or component editor.
dampingPS (dps)	doubleArray	empty
This attribute is per spring. How strongly the motion of springs are damped by the 'physical' properties of the springs. PS stands for per-spring. This attribute stores an array of data, one for each spring. The value can be edited with the spring command or component editor.
restLengthPS (rps)	doubleArray	empty
It is per spring attribute which represents the length at which springs try to stay. PS stands for per-spring. The values can be edited with the spring command or component editor.
objectPositions (opos)	vectorArray	empty
position array for the objects incident to the springs.
objectVelocities (ovel)	vectorArray	empty
velocity array for the objects incident to the springs.
objectMass (omas)	doubleArray	empty
mass array for particle objects incident to the springs.
deltaTime (dt)	time	0film
spring node may need deltaTime to compute force. It is connected with particle objects.
outputForce (of)	vectorArray	empty
output force to particle objects. It is "CACHED" so that the computePlug is called once for all nodes which are waiting for the output force from this spring node.
validIndex (vali)	intArray	empty
Indices to indicate which springs are valid.
object0 (obz)	intArray	empty
Indices of attached object(should be plug multi-index in the aObjectPositions attribute).
point0 (ptz)	intArray	empty
Indices of spring endpoints in their respective objects.
object1 (obo)	intArray	empty
Indices of attached object(should be plug multi-index in the aObjectPositions attribute).
point1 (pto)	intArray	empty
Indices of spring endpoints in their respective objects.
minSprings (ms)	integer	0
This attribute hold the shortest length of index arrays so that computeForce method will use it to get each spring without over range of the five index arrays. This will save time (don't do too many checkings) and method won't fail if some springs are missing. This attribute is affected when edit end object index arrays or end point index arrays.
manageParticleDeath (mpd)	bool	true
This attribute determines if the spring node need to do ID/Index mapping. The default value is true for this attribute. If users know that there is not any particle died, it can be set to false. With the false value, the spring node will not do particle Id/index mapping and speed up the evaluation.
idMapping (idm)	compound	n/a
This attribute holds the mapping information for the particle IDs<<==>>Index into per-particle attribute arrays. It will connected with aIdMapping of particle nodes.
sortedId (sid) intArray empty With this attribute, we get the particleIds from particle node. The particleId values are sorted in ascending order.
idIndex (idix) intArray empty With this attribute, we get the particle index positions into per-particle attribute arrays for the corresponding ids stored in aSortedId.
count (cnt)	integer	0
The number of springs in the object.
objects (obj)	Message	n/a
Obsolete. Used only to read version 1 files. Will be removed after version 2.
objCount (obc)	integer	0
Obsolete. Used only to read version 1 files. Will be removed after version 2.
lengths (lns)	doubleArray	empty
Obsolete. Used only to read version 1 files. Will be removed after version 2.
minUsed (mnu)	double	0.0
Obsolete. Not used. Will be removed after version 2.
maxUsed (mxu)	double	0.0
Min value used when springs were made Obsolete. Not used. Will be removed after version 2.
pt0Index (pzi)	doubleArray	empty
Used only to read version 1 files. Will be removed after version 2.
pt1Index (poi)	doubleArray	empty
Used only to read version 1 files. Will be removed after version 2.
obj0Index (ozi)	doubleArray	empty
Used only to read version 1 files. Will be removed after version 2.
obj1Index (ooi)	doubleArray	empty
Used only to read version 1 files. Will be removed after version 2.