rotational inertia of the mass

[chjjj]

In my model, masses are concentrated at the nodes where columns and beams meet according to the tributary mass per node. I use rigid diaphragm constraint to each floor and each floor has three freedoms: UX, UY and RZ.
So I define mass as follow:
mass $node $m $m 0 0 0 0

Can opensees calculate the rotational inertia of the mass to the centre of the rigid diaphragm automatically? If it can’t, should I define the mass as:
mass $node $m $m 0 0 0 $m*d^2
d represent the distance between the mass and the centre of the rigid diaphragm.

thanks

[fmk]

if you use the transformation constraint handler there will be
an Mz component .. T^t M T .. i.e. the same transformation that is applied to the stiffness matrix will be applied to the mass matrix .. look at documentation to see what T is.