Prevents modification of the curvature at the end opposite the match for curves with fewer than six control points.

None

No constraint.

Position

Location only.

Tangency

Position and curve direction.

Curvature

Position, direction, and radius of curvature.

Perpendicular to Edge

Sets the curve perpendicular to a surface edge.

Average curves

Both curves adjust to match each other.

Join

Joins the resulting curves.

Merge

Merge is available with the Curvature option, and it makes a single curve instead of a composite curve. If you edit this curve's control points, the location where the two original curves match will deform smoothly. You cannot explode the curve into the segments that were originally matched.