Creating a quadrilateral load

Select a load case either in the Load Description tree or using the Load Case Selector list in the Standard toolbar.
Select the Pressure and Position Units to use for the load.
Specify the magnitude of the uniform Pressure.
Define the area (footprint) of the load by specifying coordinates of the quadrilateral figure (x1, x2, x3, x4, z1, z2, z3, z4).
Specify a Y Position value to indicate the elevation at which the load is applied.
Note: The Y Loading Position must correspond to the elevation of the foundation supports.
Click the Add button. The load is added to the load case.