How do I make the edges sharp after using subdivision surface modifier? - Basics & Interface - Blender Artists Community
Subdivision Surface in Edit-Mode - Blender Development Discussion - Blender Artists Community
Subdivision behaviour is different than in any other software causing compatibility issues - #17 by postrowski5 - User Feedback - Blender Developer Talk
how do I remove those weird edges from the subdivision surface modifier, ctrl+r doesn't seem to work? (look at the small purple line) : r/blender