The technique I used above works for Framed Chimney Chases as well , just tried it to make sure on the plan I posted above , and it does work for adding a chimney after the fact too if needed, which I hadn't tried before.      I'll attach the new plan too.       Only downside is in section view you'll see the interior wall of the chase against the house , so you'd need to remove those lines in your section detail.   I used a text box on my .plan to make notes originally so the "How To" is