javatom

You can go into the layer display and find the layer "roof trim". Unlock that layer and you can then edit the frieze board and fascia.

Move the end of the wall toward the lower stair section. There will be an exact spot where it will work as you want it.

That enhanced image is not as good as the original. Zoom in on both images and you will see what I mean. I guess Artificial intelligence doesn't always make it better.

Brick is considered a veneer. The condition you show would mean there is not a direct load path. The wall above is being structurally supported by the cantilevered floor system. This would make it a non prescriptive design. It probably would work but you might want to have an engineer sign off on it. I have attached a picture of how I would do this.

Your foundation wall is not right. The bricks should be set to the exterior, not the main layer. Brick would be considered siding and would not normally bear the weight of the 2x6 wall above. The main layer should also be set to a thickness that will support the wall above. I just did this on your plan and the section view works fine. The slab will stop at the main layer and not go under it.

I have turned off the pony walls. You also need to turn on the layer that shows the floor surface.

Set the garage to have a floor and NOT be provided by foundation room below. Set the foundation level under the garage to "open below". On the floor 1, open the room dbx and to the the structure tab. At the bottom of the page, there will be an option for slabe pour number. Change it from 1 to 2. You might have to adjust a few other things but this will get you close.

Look at the moldings setting. At the bottom of the screen there will be an option to turn off "extrude inside polyline". That will make your trim board visible on the outside of the building.

This can get complicated very quickly. Many towns and counties have their own addendums. In Coeur d'Alene, ID (Kootenai County) we use IRC code books. The local addendums however, are a bit more restrictive. One example is the requirement for an engineered calculation for any opening over 6'. I imagine every local jurisdiction has a version of their own local addendums.

Use the elevation region tool. Set the region to a negative number.

This reminds me of an old joke. NASA spent millions of dollars to develop a pen that would work in zero gravity. The Russians just used a pencil.

That is probably the quickest way to do it. You might also try lowering the floor of the garage by 6". You could then add the slope and higher portions of the slab as a P solid. You might have to do some custom drawing to the section views to make it look right.

Leave the floor at an elevation of zero. Lower the grade.

You can make your foundation a pony will with the top wall type set to have siding.

The wall specification structure box has a setting for "stop at ceiling above". That might help.