Change the continuity at a blend point

Change what kind of continuity a blend curve maintains with an object its constraint is attached to.

Change the continuity at the picked blend points

Choose Curves > Blend Curve Toolbox to show an extra floating palette containing the BlendCrv Tools tab.
Choose the continuity level from the BlendCrv Tools > Constraint Continuity sub-menu.

Change how curvature continuity is calculated at the picked blend point

NoteYou can only change the curvature type of a constraint that is attached to an object, and has G2 or greater continuity.

Choose the curvature type from the BlendCrv Tools > Curvature Type sub-menu:

What is the difference between parametric and geometric curvature?

Parametric curvature: align the curvature to the isoparametric direction of the surface. This type of curvature is especially useful to achieve curvature continuity with the corner of a surface.

Geometric curvature: align the curvature to the intersection of the tangent and the normal direction of the surface.

NoteYou must use geometric curvature if you want the blend curve to be planar (all points on the curve lie in the same plane).