The Ctrl-D method works with lattices and objects that you have imported. It doesn't work with primitives. There are people doing excellant work using lattices/g2h and other methods. In general however, lattices are much larger files than you can develop using other methods. Bryce was never intended to be a general modeler and to the best of my knowledge no plans are in the works to make it so. If you want an all around modeler you need to look at another program in addition to bryce.