Use this option to define the load level used to check the lateral buckling conditions. You can access the option by clicking the appropriate icon in the Lateral Buckling Parameters field in the Member Definition - Parameters dialog.
It is necessary to include the level of load application in order to describe lateral buckling conditions. The ordinate height of load application is defined in the member section axis system. Assuming that lateral buckling occurs when loading the member in the XZ plane, only one coordinate is entered. If the load is applied at a characteristic section point - upper flange, lower, and so on, then, the coordinate value is entered automatically after an appropriate icon is chosen.