Use the following options to set what happens when you select Curves > Open/Close.
Select the amount of shape preservation when a curve is opened/closed.
Ignore does not preserve the shape of the original curve.
Preserve adds or deletes control vertices as necessary to preserve the shape of the original curve. This is the default setting.
Blend tries to create continuity on the resulting curve. It uses the Blend Bias for the amount of smoothing.
Alters the amount of continuity for the resulting curve. Large values might distort the tangency of the original curve.
Inserts a knot at the join point and lets you set a value for the Insert Parameter. This option is available only if you select Blend.
Sets the amount of influence the inserted knot has on the curve shape.
Retains the original curve after opening or closing the curve.