Buildings on the corner of 2 streets in the closed row of houses have often gabled roof shape
which is difficult to generate only by use of roof:shape=gabled.
For this geometry I suggest the new description ‘’‘roof:shape=L_gabled’‘’
See example:
What would be helpful is an Area with three height-nodes for skillions (that would be easier as roof:slope:direction) and four height-nodes paraboloid shapes. Your proposal at “F3DB Workshop Erlangen” would works if the height-nodes are shared or -if necessary- not shared.