Adds a Transform constraint to the selected hair curves. This is like constraining the points to a block of jelly at the start frame. Unlike the Stick constraint, when the constraint node is rotated or scaled it will pull along the constrained points. The transform on the constraint node is effectively the transform for this block of jelly. This is useful when constraining hair to fall along a contact point, like a shoulder. Also this can be used to simulate hair being grabbed and twisted by a hand. If you animate the constraint's scale the hair can be pulled together or pushed apart. See Set up hair constraints.