Creating a Walk-out Basement

Reference Number: KB-00376
Last Modified: July 15, 2021

The information in this article applies to:



I am trying to create a walk-out basement on sloping terrain. How do I do this?  

Exterior view of home with walkout basement and sloped terrain


By default, the program will produce a flat building pad under your plan, which is helpful in many situations but not when you want to model a walk-out or daylight basement on sloping terrain. 

To create a sloped lot

  1. Select Terrain> Create Terrain Perimeter  from the menu.

  2. Select Terrain> Elevation Data> Elevation Line from the menu, then click and drag to create elevation lines across the terrain.  

    Terrain Perimeter with Elevevation lines and an Elevation Region

    • In this example, the angled Elevation Lines on the left side of the terrain have an Elevation value of -160". 

    • The two vertical lines to their right have an Elevation of -96". 

    • The next vertical line to the right has an Elevation of -6", and the two vertical elevation lines on the right side of the terrain have an Elevation of -14".

    • You can also create flat areas with a single elevation using the Elevation Region  tool. In the above image, a rectangular Elevation Region with an Elevation of 6" is shown with an angled fill.

  3. When your elevation data is in place, select Terrain> Build Terrain  from the menu. The program automatically generates contour lines between the Elevation Lines that you drew.  
    Terrain Perimeter with contour lines   

  4. To see the results of your elevation data, view your terrain by selecting 3D> Create Perspective View> Perspective Full Overview .  

    Perspective Full Overview showing the final shape of the terrain

To create a walk-out basement

  1. Create a Terrain Perimeter and use the Elevation Data tools to create varying elevation as demonstrated in the section above.

  2. Build the first floor of your plan at the location of the slope in your terrain. You may need to adjust either the floor height or some of the elevation data up or down a bit to get the first floor to rest just right on the terrain.  

    Structure placed in terrain with elevation lines

    • In this example, the four Elevation Lines on the left side of the terrain have an Elevation value of -96".

    • The single line that intersects the structure is at an Elevation of -36".

    • The two lines on the right are at an Elevation of 0."

    • The floor height for the structure has not been adjusted.

  3. Next, select Build> Floor> Build Foundation  to create a basement level with stem walls of at least 100 inches (8 feet plus 4 inches for the foundation slab).  

  4. You can change the walk-out wall to a framed wall type such as Siding-6, or perhaps a pony wall. You can also change the exterior surface of visible concrete walls to a more attractive material such as stone or brick.  

  5. Finally, place windows and doors in the exposed part of your walkout basement and then take a look at the results by selecting 3D> Create Perspective View> Perspective Full Overview .