In my situation each link betweed nodes is represented by it's own line. When a ToNode has multiple links from other nodes each link is represented by it own line which is just the way I need it. I do have one issue though...When Node A links to Node B more than once I only get one line (slighly thicker so I think two lines are actually being rendered). What do I need to do to get more than one line to be visible.
I used curviness earlier and switched to no curveness because I liked the look better. I did find out that when drawing multiple links between two nodes that both lines render. I found out that when moving one of the nodes that multiple lines would (sometimes) become visible. What I have decided to do is higlhight the a multiple link and interactivly ask the user which link to use depending on the context. Sometimes I can determine what to do depending on the parent child relationship. When I can't I will present a link pick list.