To create a point on curve locator
As you drag, you move the curve point. The curve point’s position is defined in terms of the curve’s U parameter.
The Point On Curve Options window appears. See Create Deformers > Point On Curve.
Maya creates a locator at the curve point with the default point on curve options. The curve point is now constrained to the locator.
For each curve, Maya creates a least squares modifier node (default name: leastSquaresModifiern).