Use this procedure to create a body modifier and add it to a stair.
You can create a three-dimensional (3D) body modifier from a mass element, a mass group, or any other AEC object with mass. You can also create body modifiers from ACIS solids or blocks that form 3D bodies. You must place the object in the location you want in the drawing before defining the object as a body modifier.
The following illustration shows you how to use a mass element as a body modifier to add to a stair stringer component.
Adding a body modifier to a stair component