drawing path on the polygon surface and insert objects along that path

Hi, I would like to write the Editor features which will do drawing Spline along the selected polygon and put some of the objects made in Prefab along that SPline.. I am very new to Editor Features and can someone guide me to the right direction?

Debug.DrawLine allows you to draw a line along certain edges, not a full answer to your question, but hopefully a push in the right direction: http://unity3d.com/support/documentation/ScriptReference/Debug.DrawLine.html