Connection Combinations
Restrictions on the combinations of connections follow.
• You cannot add a fillet to the last point on a curve through points. When you click 
OK to complete the curve through points, if the last point set contains a fillet, the fillet is removed.
OK to complete the curve through points, if the last point set contains a fillet, the fillet is removed.• A point set with a straight line connection that has a fillet added cannot exist after a point set that uses a spline connection.
• A point set with a spline connection cannot exist after a point set that uses a straight line connection and an added fillet.
• To place a curve on a surface, the connection type for all point sets must be spline. If a point set does not use a spline connection, either change the connection type to spline, or remove points sets defined with straight line connection from the curve definition.
• Tweak curve can be used only for a spline curve created through two points.