Adds a Stick constraint to the selected hair curves. This is like attaching sticks from the constraint to the point set, where the sticks may rotate freely about the constraint center. This is similar to the Rubber Band constraint, except that when the distance between the constraint and points is less than the start distance a repulse force is also applied (in addition to the attractive force when the distance is greater). This tends to keep all the constrained points at a fixed distance (the distance at the start frame) from the constraint center. See Set up hair constraints.