I created a custom builtin for my custom fire place

[aero1107]

After you create the hearth when designing your custom fireplace you can actually create custom built-ins using the soffit a half wall adjusted to the height you wanted but i recommend using at least a 16" thickness. You just add a door casing to your half wall and adjust it to the height you want to make your custom built-ins. Then you can add the custom mantle above it and it makes the fireplace complete. I was trying to create this but the help section didn't give me that option.