Considering it's 3Ds Max... Bridge the edges on the weirdest angels and then cap the holes by selecting borders? And that is if you really arent worried about the topology.
Use Bridge in sections. Don't do it all at once it's horrible at figuring it all out in one action. Select 10 edges or so on one side and around the 10 other equivalent ones on the other side. It's a pain but it's better than cap + slicing by hand.
thanks guys, yeah I ll often use bridge for this but I have a lot of glass pieces divided in even smaller pieces... so I was wondering if there was something more "automatic" ! I dont really care for crappy geo being generated to fill the holes, is more because I am shading some glass pieces and to get proper refraction I…