Hi,

LayeredLayout doesn't have built-in support for Bezier links. You could change the links' Style to Bezier after the layout is applied. You will first have to save the control point positions as set by LayeredLayout, then insert two additional control points for each segment at appropriate locations to make the segment joins nicely curved. Finally assign the points back to the Bezier links ControlPoints property.

I hope that helps,
Stoyan

That's the right order. Bezier links have to types of control points, ones through which the curve passes, and ones that just attract it. Each segment of the link has two points of the first kind at its ends, and two intermediate points of the second kind. The points you get from LayeredLayout correspond to the first kind; the links should pass through them to reuse the path found among nodes by LayeredLayout. For each pair of such points you get from LayeredLayout, you should insert two intermediate points to attract the Bezier curve in some direction. An additional requirement is that the intermediate points that are adjacent to the join point of two segments should lie on the same tangent line, so that the link remains curved at the join.

You should add 3 * link.SegmentCount + 1 points when the link.Style is Bezier. Is that how much points are in pColl?

The method you are using should work:

a.ControlPoints.Clear();
a.ControlPoints.AddRange(pColl);

You should just make sure that when the link is Bezier, you add 3 * segments + 1 points. Having 2 points when it is a straight line with one segment is correct, because straight-line links don’t have the intermediate control points. So between each pair of point set by LayeredLayout for the polyline links, you should now insert two intermediate control points.