For years, SketchUp users relied on the tedious "Follow Me" tool or clunky extensions to add rounds. Then came (by Fredo6) and, more recently, native improvements.
Let’s be honest: Nothing screams "beginner SketchUp model" like a sharp, knife-edge corner on a piece of furniture or a building column. In the real world, almost nothing is perfectly sharp. Material thickness, safety, and aesthetics demand filleted (rounded) edges. Rounded Corner Tool Sketchup