Hi Marco, yes it sounds like the "closest point" mode for project isn't reliable enough for you, the direction mode should work better. Or another possibility could be the steps that I mentioned earlier - determine if any curves intersect the outer boundary (use the "intersect" factory from the Construct > Curve > Isect command and see if it generates any result), remove those then send the rest to planarsrf to generate loops. Use the hole loops to identify the curves they came from by seeing if any start/end points match between the curve segments and the hole edges.

- Michael