Thanks Jim. I guess I was confused.( on a post for example) I thought you would lay out the chalkline as close to the edge as you can,(the last straight line that you could snap within the timber) , of your timber exterior reference face, and this would become the last straight in the timber and also the building. I thought to place the crown out ,as I thought its natural curvature towards the the interior of the frame would help fight the rafter thrust more , but maybe this is incorrect as well? It definitely makes more sense like you said to place the crown in when considering enclosure. thanks tb