ALL YOU WANTED TO KNOW, BUT NEVER DARED TO ASK ABOUT CARBON RIGID "BODIES"!
Carbon is built on a next generation dynamics architecture where there is no explicit notion of soft bodies or rigid bodies.
They are composite constructions of their constituent parts, which opens the door to exciting possibilities.
Check out the new User Guide entry in the docs for full description of these concepts - applicable to Carbon in Houdini or Maya.
On this web page, https://www.numerion-software.com/index.php/209-carbon-rigid-bodies we explain how to setup Carbon Rigids + Shape + Body to create a Carbon Rigid "body"