How do I create a nonprismatic beam section?
Go to the Define > Frame Sections command and in the Define Frame Properties form click on the Add I/Wide Flange drop-down list and scroll down and click on Add Nonprismatic. On the Nonprismatic Section Definition form you may define multiple segments for each beam that vary linearly, parabolically, or cubically. If used with certain insertion point frame assignments, users can model nonprismatic gabled sections (see figure 1 below) which flair only on one side.
