How to force different drawing of edges for those which use the same source and target nodes that are fixed in position using Graphviz (neato engine)

Question

I'm trying to use Graphviz via its C library to draw edges between nodes which are fixed in position. The problem, however, is that many of the edges use the same source and target nodes, and for some reason they get drawn using the exact same coordinates, resulting in complete overlap.

Is there some obvious attribute that I've forgotten to set which causes this behavior? I'm using the code provided from http://mupuf.org/blog/article/34/ since I'm using Qt to draw the edges.

Answer 1

Apparently, this doesn't work when splines="true". Leaving it unset or setting it to "false" invokes the behaviour I want.