How a house is built
The roof shape
Rafters and trusses make the roof shape and tie the walls. This house shows a gable, a hip, and a dormer.
Arrow keys turn the house. Plus and minus, or the zoom buttons, change the zoom. A horizontal drag turns it after you tap the drawing. Reset view returns to the step camera.
The drawing needs WebGL. The notes on the page still stand.
Site-built rafters are assembled on site. A conventional ridge-board roof uses ties to resist outward thrust; a designed structural ridge-beam roof uses a different support arrangement. In a conventional tied-rafter roof, a rafter tie or suitably connected ceiling joist keeps the two eaves from spreading. A hip rafter runs to an outside corner. A valley rafter sits where two slopes meet in a gutter. A dormer is a small roof and wall cut into a slope, and it has to flash into that slope.
This house has an east gable, a hip toward the balcony, a dormer on the front, and lower roofs on the garage and the porch. Trusses can make the same shapes. The planes are drawn. The members inside them are not.