Warning: Non-system panel families cannot be used for non-rectangular panels. If your panel is simple, create an appropriate panel type derived from the system panel family. If not, try making the panel in the wall or roof rectangular, and then using a panel family of the desired (non-rectangular) shape. The wall will then conform to the non-rectangular shape of the panel.
Issue: A non-system panel, such as a glazed or empty panel, cannot have a non-rectangular shape.
Solution: This problem might occur if a curtain wall with non-system panels joins to a roof, and the curtain wall does not have a rectangular shape. It would also occur if you create a non-rectangular wall profile and then change that wall to a curtain wall with non-system panels.