A new feature has been added to easily model a rigid floor diaphragm without the need to specify a master joint at each. When specified, this command directs the engine to perform the following:

1. calculate the center of mass for each rigid diaphragm (where master joint is to be located) considering the mass model of the structure. The mass must be modeled using the new mass reference load feature.

2. create, internally, an analytical node at the center of mass location to be included during analysis (unless a master node is specified) if an existing analytical node exists at this point, then the existing joint is used in lieu of creating a new joint.

3. search all nodes available within a diaphragm and add them as slave nodes; with the master node located at the center of mass for the diaphragm (or at the specified master node)