The asymmetric roof addition beat me up pretty hard for about three days, but in the end I won out. Now I need to look at the hip roof and how best to deal with multi pitches…
With the hip roof we are now talking about four different possible top plate heights with four different possible pitches, birdsmouth cuts, and rafter depths.
If one is to assume that the fascia boards all line up (gutters), then the top plates heights are actually driven by the roof overhang and the pitch of each roof plane. Only one roof plane (Plane A) will actually have its plate height set (the zero or base height of the roof), the other roof planes’ top plate heights will be automatically calculated.
I suppose there is always the possibility where the fascia don’t line up but I think this is more the exception than the rule, correct me if I am wrong.
As I’ve given this some more thought it occurred to me that typically the designer will set the roof pitches from the outset. Then, in order to get the fascia to line up, he/she can either adjust the overhang or the top plate height (assume that the birdsmouth cut is set to some value). So depending on the situation the user may want the plugin to calculate either the overhang (same top plate height) or the top plate height (same overhang). I will need to give this some more thought.
If the user keys in a numeric value for the overhang (roof planes B, C or D) then the edit menu can automatically set the delta height (top plate heights) for each respective roof plane to “AUTO”. Likewise if a value is keyed in for the delta height the HTML form can set the respective overhang(s) to “AUTO”.