Project to Z Plane

So, you've gotten a civil survey or another CAD file that has geometry at different z values (heights).

A few fixes:

1. "Flatten" This command occasionally works, but it tends to only move some geometry, rendering it essentially useless
2. Manually change "Z" values in the properties window. This is a fine fix, but can be time consuming if there is a lot of geometry on multiple layers
3. Use this command by selecting the geometry and copying and pasting the following into your command line:

(command "MOVE" (ssget "x") "" "0,0,0" "0,0,1e99")

(command "MOVE" (ssget "p") "" "0,0,0" "0,0,-1e99")

I have no idea how it works but it does the trick!

Sarah confirmed that this works with blocks and groups!