If there’s a top-billed feature in Revit 2021, the new ability to create slanted walls is it.
In Revit 2021, users can utilize the Cross-Section parameter when creating or modifying a wall to make it slanted. The Angle from Vertical parameter then specifies the wall’s angle from -90 to +90 degrees, where zero degrees is vertical. It is possible to set windows or doors in a slanted wall, but you’ll have to specify that it should follow the wall angle with the Orientation Wall Instance Property.
Slanted walls are able to be used as architectural, structural, or curtain walls in your projects, and can be edited in plan, elevation, section, 3D orthographic, and perspective views.
In general, the way you interact with slanted walls will be very similar to the way you interact with vertical walls (you can change an existing vertical wall to a slanted wall and vice versa), with just a few exceptions.