I have not had a chance to get back to my 3d printer over the weekend. I am working in Architectural Desktop (AutoCAD) and have found a sequence that works that I want to share.

When working with objects in Architectural Desktop:

Change to 3d view

Type Masselement, convert, and then pick the elements to convert to a single mass element.

Right click the created mass elements and choose Convert to -> 3D solid.

Export -> Other Formats, and then save as .stl (Lithography)

When working with objects in COINS (Construction Industry Solutions) the wall objects can be changed to show the studs in the walls rather than the walls. It is used for estimating.

Select the walls,

Right Click and choose frame tools > Explode to Structural

Press enter to create structural members out of all the framing members.

Do the same as above.

At first this did not work so I had to use Union to join the structural members first. I found this out when I was trying to scale things in Architectural desktop before I realized you could scale directly in slic3r.

I share this for a couple of reasons. 1. So I can reference it in here when I forget a step as I am sure I will. 2. if anyone else is working in AutoCAD, or Architectural Desktop maybe they will find this useful.