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.

There are actuators:
Carbon Rigid
Carbon Actor
Carbon Soft
which are dynamic objects that can be constrained.

Then there is a Carbon Shape, which can either be solid or deformable and is defined through a mesh with fatness / thickness properties.

And there is a Carbon Body, which is a true collision entity, based on the relationship between an actuator and a shape.

Check out the new User Guide entry in the docs for full description of these concepts - applicable to Carbon in Houdini or Maya.
Carbon for Maya docs https://download.numerion-software.com/guide-actoretc

We also provide a macro in Carbon for Maya, to generate composite Carbon objects  = Rigid "bodies".
This tutorial explains more about setting up a a chain link belt. https://vimeo.com/616110670

This tutorial explains more about Carbon Rigid mass boxes https://vimeo.com/617005202

This forum entry explains how to move a Carbon Rigid Body from one mesh to another 
https://www.numerion-software.com/index.php/forum/tip-of-the-week/425-editing-carbon-rigid-bodies

There are also several other forum entries with scripts to assist editing Carbon Rigid "bodies" here https://www.numerion-software.com/index.php/forum/tip-of-the-week

Finally you will find various downloadable examples using Carbon Rigid "bodies" in the documentation here for Maya here https://download.numerion-software.com/downloads