The Member Modelling dialog contains settings relevant to how a member is represented in a true physical model of the frame. At the moment the only setting contained in the dialog identifies if the member is a beam, column, brace or another component within the model.
To set the member modelling options for a member
§ Select the member or members to be modified
§ Choose Member Modelling… from the Frame menu

§ Select which component of the frame the member represents.
§ Click on the OK button
The component property of the member identifies what component within the frame that a member represents such as a column, primary beam or a brace. This information is used within the program help identify the most significant member at a connection. This is in turn used to automatically compute the cut-off distances at each ends of a member used in rendering of the frame.