> and something else to smooth corner point?

To add a smooth point without changing the shape of the curve, use the same "Add pt" tool, but make sure the curve you click the point on has its edit points turned off. Turn them back on after you have added your points.

You can also add a corner point to a curve in this same way, by checking that option.

When you are in "Add pt" and you click directly on a curve (instead of on the line between two control points), you will insert a point in the general area that you clicked on but keep the shape of the curve exactly the same.

- Michael