Hi ckerch,

This is how I'd do this. This method is valid for AS 5000, AS 4000, AS 3000 V10 and IDS
(I used 3 odd materials to clarify the explanation)

1 --> draw your gable wall--> imagine the H= 90"--> insert the wainscot (in this example I used a wainscot with brick texture H= 60")
2 --> Power Tools--> Trim Designer--> create a trim (flat) with height==> Wall H- Wainscot H ==> In this case 90"-60"= 30"
3 --> Live view--> Trim--> Crown Molding--> Apply the new trim (H=30") (With wood texture in this case)
4 - texture / color the wall as necessary (in red in this case)--> only the gable will be textured

You can add your doors / windows before or after the above steps

Check this image








Hope this helps

Patricia