pointOnPolyConstraint

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This node implements a pointOnPolyConstraint. Each constraint has a set of targets that are connected under the target attribute, a single constrained object that is connected to the constraint* attributes, and possibly other information to help compute the correct results. In the case of the pointOnPolyConstraint, the extra information is stored in offsetTranslate and offsetRotate attributes.

The pointOnPolyConstraint node can have any number of target inputs. Each target is connected to attributes inside a single element of the target attribute. For example, the first target object would be connected elements of target[0], the second target object would be connected to elements of target[1], etc. The elements of each target are: targetMesh, targetUVSetName, targetUV, and targetWeight.

The elements of each target are normally connected to the target objects as follows:

pointOnPolyConstraint attribute	connected to
targetMesh	worldMesh
targetUVSetName	set to e.g. map1
targetUV	set to a pair of uv coordinates
targetUseNormal	set to 1
targetWeight	set to 1.0

The targetWeight attribute is not generally connected to the target object. Instead, it may be animated by other means to adjust the weighted average computation for the target point.

The pointOnPolyConstraint node uses these inputs to compute the world space position of a point on the surface of each target object. If no point on the surface matches the provided uv coordinates, or the uv set name does not match a uv set on the object, then that target object is ignored. The node then computes a weighted average of the these points. This weighted average is called the target point.

The node also computes a surface normal and a tangent vector at each of the points identified by the uv coordinates. The tangent vector is taken to be the local u coordinate tangent. These normals and tangents are also averaged, and together define an orientation - the target orientation.

The constrained object is connected to the constraint* attributes. For a pointOnPolyConstraint, the constraintRotatePivot, constraintRotateTranslate, and constraintParentInverseMatrix are inputs to the pointOnPolyConstraint. The attributes constraintTranslate and constraintRotate are the only outputs.

The pointOnPolyConstraint node computes an output translation value such that the pivot point of the constrained object is offset by offsetTranslate from the target point.

The pointOnPolyConstraint node computes an output rotation value such that the orientation of the constrained object is offset by offsetRotate from the target orientation.

Although the all the constraint nodes inherit from transform, they do not actively use any of the attributes from transform.

aimConstraint, geometryConstraint, orientConstraint, normalConstraint, parentConstraint, pointConstraint, poleVectorConstraint, scaleConstraint, tangentConstraint, lookAt

constraintParentInverseMatrix, constraintRotate, constraintRotateOrder, constraintRotatePivot, constraintRotatePivotX, constraintRotatePivotY, constraintRotatePivotZ, constraintRotateTranslate, constraintRotateTranslateX, constraintRotateTranslateY, constraintRotateTranslateZ, constraintRotateX, constraintRotateY, constraintRotateZ, constraintTranslate, constraintTranslateX, constraintTranslateY, constraintTranslateZ, offsetRotate, offsetRotateX, offsetRotateY, offsetRotateZ, offsetTranslate, offsetTranslateX, offsetTranslateY, offsetTranslateZ, restRotate, restRotateX, restRotateY, restRotateZ, restTranslate, restTranslateX, restTranslateY, restTranslateZ, target, targetMesh, targetU, targetUV, targetUVSetName, targetUseNormal, targetV, targetWeight

Long name (short name)	Type	Default	Flags
target (tg)	compound	n/a
bundle of matrix, input position, and weight
targetMesh (tm) mesh NULL input mesh to which the object should be constrained
targetUVSetName (tnm) string NULL input uv set name
targetUV (tuv) double2 input uv coordinates targetU (tu) double 0.0 input u coordinate targetV (tv) double 0.0 input v coordinate
targetUseNormal (tun) bool 1.0 controls whether the surface normal affects the target orientation
targetWeight (tw) double 1.0 input weight for the position
constraintParentInverseMatrix (cpim)	matrix	identity
inverse of the parent matrix of the object
constraintRotatePivot (crp)	double3
object rotate pivot
constraintRotatePivotX (crpx) distance (double) 0.0cm object X rotate pivot
constraintRotatePivotY (crpy) distance (double) 0.0cm object Y rotate pivot
constraintRotatePivotZ (crpz) distance (double) 0.0cm object Z rotate pivot
constraintRotateTranslate (crt)	double3
object rotate pivot translate
constraintRotateTranslateX (crtx) distance (double) 0.0cm object X rotate pivot translate
constraintRotateTranslateY (crty) distance (double) 0.0cm object Y rotate pivot translate
constraintRotateTranslateZ (crtz) distance (double) 0.0cm object Z rotate pivot translate
offsetTranslate (ot)	double3
object translate offset
offsetTranslateX (otx) distance (double) 0.0cm object X translate offset
offsetTranslateY (oty) distance (double) 0.0cm object Y translate offset
offsetTranslateZ (otz) distance (double) 0.0cm object Z translate offset
offsetRotate (or)	double3
object rotate offset
offsetRotateX (orx) angle (double) 0.0deg object X rotate offset
offsetRotateY (ory) angle (double) 0.0deg object Y rotate offset
offsetRotateZ (orz) angle (double) 0.0deg object Z rotate offset
constraintTranslate (ct)	double3	0.0, 0.0, 0.0
output point position
constraintTranslateX (ctx) distance (double) 0.0cm output X point position
constraintTranslateY (cty) distance (double) 0.0cm output Y point position
constraintTranslateZ (ctz) distance (double) 0.0cm output Z point position
constraintRotate (cr)	double3
output orientation
constraintRotateX (crx) angle (double) 0.0deg output X orientation
constraintRotateY (cry) angle (double) 0.0deg output Y orientation
constraintRotateZ (crz) angle (double) 0.0deg output Z orientation
constraintRotateOrder (cro)	enum	0
Input constrained object rotate order value.
restTranslate (rst)	double3	0.0, 0.0, 0.0
The rest translation defines the output of the constraint when all weights are zero. It is used when the enableRestPosition attribute is true.
restTranslateX (rtx) distance (double) 0.0cm rest x translation
restTranslateY (rty) distance (double) 0.0cm rest y translation
restTranslateZ (rtz) distance (double) 0.0cm rest z translation
restRotate (rsrr)	double3
rest orientation
restRotateX (rrx) angle (double) 0.0deg rest X orientation
restRotateY (rry) angle (double) 0.0deg rest Y orientation
restRotateZ (rrz) angle (double) 0.0deg rest Z orientation