Create slanted walls using the wall instance parameters.
This video demonstrates the following:
When your design calls for a slanted wall, create the wall as you would a vertical wall and use constraints in the Properties palette to apply the angle.
Select the wall, on the properties palette, click the Cross-Section Instance property and select Slanted. Then specify the angle you want to apply to the wall. You can select a value between -90 and +90 degrees. For this wall, we will apply an angle of -25 degrees. You can also use grips at the top of the wall adjust the height or the angle.
You can place doors and windows in slanted walls just as in vertical walls. Once the door or window is placed, select it, and then select vertical or slanted orientation in the Properties palette. Selecting Slanted orientation places the window or door at the same angle as the wall.
Keep in mind there are some restrictions when working with slanted walls. Check the help documentation for best practices.
Use slanted walls for greater flexibility as you create your designs.