*SetBodyInertia() - symmetric body pair
Sets the mass properties of a symmetric body pair.
Syntax
*SetBodyInertia(body_name, LEFT|RIGHT, mass, 
                                                ixx, iyy, izz, 
                                                ixy, ixz, iyz)
    Arguments
- body_name
 - The variable name of an existing body pair.
 - LEFT RIGHT
 - If LEFT is specified, the properties are assigned to the left body, and the right body properties are made symmetric to the left body.
 - mass
 - The mass of the specified side of the body pair.
 - ixx, iyy, izz, ixy, ixz, iyz
 - The moments of inertia of the specified side of the body pair.
 
Example
*Body(crank, "Crank", crank_cm)
*SetBodyInertia(crank, LEFT, 3, 
10000, 10000, 10000, 
0, 0, 0)