Update: apparently Houdini has a beta tool for that under the Labs section called "edgegroup_to_curve", it will save you a couple of extra nodes ;)
In 3ds max it's a matter of hitting a button, well not in Houdini it had to be difficult, but dont forget that it's procedural so if you mesh is deforming you'll get a deforming line as well ;)
One thing to mention is that this method might produce overlapping curves, so just add a delete sop to clean it out.
This works so well. Thank you!
asd