The information in this article applies to:
How can I create a single wall that has drywall where it is serves as an interior wall, and siding where it serves as an exterior wall?
In some situations, a single wall may need to serve as both an exterior wall with sheathing and siding materials and also an interior wall with drywall.
A classic example of this is where a bump-out or addition meets the gable wall of a taller structure. The roof over the addition will butt against the taller gable wall, and the gable wall will require siding above the roof and drywall below it.
This condition can be easily achieved using the Lower Wall Type if Split by Butting Roof setting located in the Wall Specification dialog. However, it's important to finalize the footprint of your plan, particularly the floor heights and the positioning of your ceiling and roof planes, prior to enabling this setting.
If you open this particular wall up to specification again and access the Wall Types panel, you will now notice that it has been specified as a pony wall. The major difference between this particular wall and a normal pony wall is that the adjacent roof's position is determining where the wall types change.