For roof mass generation, building masses are created using the dimensions of the roof panels, including overhangs. You can choose whether to enter the sloped or projected self-weight.
For flat roofs, if all the blocks have the same number of levels and all the roofs are flat, then the masses are generated in the same manner as floor masses. If not, the masses are generated using the dimensions of the blocks that were used to create the roofs. Refer to Uneven Block Heights for adjustments that may be necessary in this case.
Snow masses are generated using the projected of the roof panels. .