The best tutorials in this case are the good examples set by sucessfull mappers such as to one in this area. To learn and study it you/they will have to open an editor to find study it of course, or you or someone seeing that their is a need, could write and submit an article to the Wiki if you wished. to solve the problem. http://www.openstreetmap.org/?lat=52.216242&lon=-0.066028&zoom=18&layers=M after you have read and used the excellent info pointed to by aseerel4c26 http://wiki.openstreetmap.org/wiki/Roof_modelling

The best tutorials in this case are the good examples set by sucessfull mappers such as to one in this area. To learn you/they will have to open an editor to find study it of course, or you could write and submit an article to the Wiki if you wished. http://www.openstreetmap.org/?lat=52.216242&lon=-0.066028&zoom=18&layers=M after you have read and used the excellent info pointed to by aseerel4c26 http://wiki.openstreetmap.org/wiki/Roof_modelling