Mean crease don't work


Why mean crease don’t work? I have to make a square window like on the last image and don’t want to add new edges. How fix this problem? Object has subsurf modifer.


Extend your edge selection to include the adjacent edges, then Shift-E for edge crease, so:

Be aware this will add flat spots to your model around the hole.

Thanks! So simple if you know and hard when don’t )