Rhino introduced the SubD command bar in releases 6 and 7. If you still have the previous releases (4-5) one solution I've experimented with is to bundle Rhino 5 with free art modeling software. Even though I have the Rhino 7 release, I can't load it on one of old laptop of mine, so I tried SCULPTRIS, freely downloadable from the web: https://en.wikipedia.org/wiki/Sculptris Files can be exchanged in .OBJ. One limitation of Sculptris is that it sometimes has difficulty importing complex objects. Another limitation of Sculptris is that the starting object to be modeled is a sphere, when instead it would be preferable to start from a cube. This is only a starting free solution, which can be implemented with other more complete artistic software.