Path Constraints Types
Path: The 'Path' constraint will bind an item to a user generated curve or the weighted average of multiple curves affecting both its position and rotation values orienting it to face along the curves normal direction. Once constrained, the 'Percent' amount will control the items position and rotation along the length of the curve. This setting can be animated for items moving along the path.
Path Position: The 'Path Position' constraint will bind an item to a user generated curve or the weighted average of multiple curves affecting its position values only. Once constrained, the 'Percent' amount will control the items position along the length of the curve. This setting can be animated for items moving along the path.
Path Normal: The 'Path Normal' constraint will match an items rotation to the normal direction of a particular position along the curve. Once constrained, the 'Percent' amount will define the items rotation based on that positions normal direction.
Path Constraints
Path Percentage: Defines a position along the path to which the item will be constrained, 0% being the start of the curve (represented by the small circle around the first curve vertex) and 100% the end of the curve. Paths can be open or closed.
Path Offset: This control can be used to offset the point along the curve from the position specified by the Path Percentage control above. This can be used to specify a starting offset along the curve or to animate some variation into the constraint position for example.
Wrap: By default, constrained items will stop when they reaches either end of the curve, when enabled, 'Wrap' allows the item to continue it's motion from the start of the curve. For example, if the Percentage channel is set to animate from 0% to 200% then the constrained item will travel along the curve twice.
Note: The following controls are not used by the Path Position constraint.
Roll: This control specifies a rotation around the axis that's aligned to the curve.
Axis: This is the axis of the constrained item that will be orientated along the curve.
Negative Axis: Inverts the defined 'Axis' from the default positive direction, toward the negative direction.
Local Up Vector: By default the Path and Path Normal constraints will use the values in the Up Vector controls as World coordinates. However this checkbox allows you to specify that these should be interpreted as Local coordinates relative to the transforms of the Curve mesh item. This is useful if the Curve mesh is animated or transformed in any way.
Up Vector: When 'Local Up Vector' is enabled, this XYZ value will be used to specify the Up Vector direction as used in the Path and Path Normal constraints.
