The pointOnPolyConstraint node is created when you create a Point on Poly constraint. See Create Point on Poly constraints.
You can access these attributes in the Channel Box when you select a pointOnPolyConstraint node, or in a pointOnPolyConstraint tab of the Attribute Editor under the Point On Poly Constraint Attributes and Extra Attributes headings.
When a constrained object’s Lock Output attribute is on, you can only manipulate its constrained channels by transforming its driver object. When a constrained object’s Lock Output attribute is off, you can directly manipulate its constrained channels, without having to transform its driver object.
For example, when the Point on Poly constraint’s Lock Output attribute is off, you can change the position of the constrained object without having to move the constraining mesh object.
These fields let you offset the position of the constrained object from the position of the constraining mesh.
These fields let you offset the rotation of the constrained object from the rotation of the constraining mesh.
Displays the constrained object’s current position. This value can be useful when specifying the Offset Translate value. This field is read-only.
Displays the constrained object’s current rotation. This value can be useful when specifying the Offset Rotate value. This field is read-only.
If your Point on Poly constraint includes multiple constrained objects, you can also set weight and UV attributes for each object. See Extra Attributes.