Comment 5 for bug 650870

Listed among the known issues in the release notes for 0.46:
«Also, sometimes after roughening, further tweaking of a path becomes impossible with this diagnostic:

 WARNING **: Shape error in ConvertToShape: directedEulerian(a) == false

All these problems stem from the livarot library that we use for geometric manipulation of paths. Fortunately, livarot is scheduled for replacement by lib2geom, a new library now in development, so hopefully these issues will be addressed then. »
<http://wiki.inkscape.org/wiki/index.php/Release_notes/0.46#Known_problems>