With Toolbag 4, we’ve added Catmull-Clark subdivision. This means you can bring in your subdivision cage mesh from your 3D application, apply subdivision, and adjust the Subdivision Level directly in Toolbag. This works well if you need clean subdivision surfaces and want the flexibility to change the detail level on the fly (i.e., keep it low when working and turn it up for final renders.) Catmull-Clark subdivision is a great option for hard surface bakes too, as you no longer need to freeze your subdivisions down to polygons before exporting, which means faster load (and reload) times. The Catmull-Clark mode also includes a Sharpen Corners option, which retains the shape of open edges.