For hard surface modeling, there are two main workflows, each usable in a destructive or non-destructive manner. This exercise is about replicating the cube on the right side of the viewport.

1. Direct modeling

   • Destructive: Select edges and bevel them with Ctrl + B. Right-click → Shade auto-smooth.

   • Non-destructive: Select edges, set a Bevel Weight of 1 (in Edit Mode: N-side bar → Transform). Add a Bevel Modifier set to Weight mode. Right-click → Shade auto-smooth.
     
     

2. Subd modeling

   • Destructive: Add a Subdivision Surface modifier. Select corner edges and bevel them. Fewer loops are needed since the modifier already smooths the shape. Add support loops to top and bottom faces to "crease" them. Delete the top and bottom n-gons. Select boundary loops and use Ctrl + F → Grid Fill. Right-click → Shade auto-smooth.

   • Non-destructive: Add a Subdivision Surface modifier. Select top and bottom faces and crease them. Select corner edges, set Bevel and Crease Weight to 1. Add a Bevel Modifier set to Weight mode and match the corner radius. Note: Clamp Overlap may prevent similar corner radius - this is a limitation due to the Subdivision modifier. Right-click → Shade auto-smooth.