help lowering garage floor

[DH7777]

I am working with a plan that will have a monolithic slab foundation. The garage floor will be all poured at the same time but dropped 3 1/2" below the main slab. How do I do this?

Here is what I did. Drew the main floor plan(including the garage) build terrain perimeter, went room by room and in  Rm Specification/Structure and checked the monolithic slab foundation box. 

In the garage, I did the same but the stem wall box is not on and will not let me adjust it. Am I approaching this wrong? I just got started so there is not much going on with this yet. Attach is the file.

2282.plan

[Alaskan_Son]

A lot of various ways to go about this, but the key thing here is that you need to set your garage floor to have a negative elevation (this is how you tell the floor to drop down).

[DH7777]

25 minutes ago, Alaskan_Son said:

A lot of various ways to go about this, but the key thing here is that you need to set your garage floor to have a negative elevation (this is how you tell the floor to drop down).

Well as I was waiting I did figure something out. I never "built a foundation" I just labeled rooms as Monolithic slab foundation. So I "built the foundation as monolithic slab and bam! There it was already dropping the garage floor 3.5". But not on the plan I sent, I will have a slab covered front porch dropped as well(same as garage) Do I need to start over as solver suggested? I can open Rm Spec for the porch and it shows stem wall at 4", Floor to SWT 0", SWT to ceiling at 109 1/8"  What is SWT?