In many buildings, rafters have been replaced by engineered trusses (trussed rafters), normally because of span limitations and/or roof load (weight from above).
Carpenters build rafters to frame the pitch of a roof. Roof pitch is measured as rise over span (a unitless fraction). In the United States slope is given in units of pitch for the ratio of inches (in) rise per 12 in of run or inches of rise per 1 foot (ft) of run. For example, "4:12 pitch" would mean 4 in of rise over 12 in of run and "4 pitch(es)" would mean 4 in of rise over of run. In Australia, a roof pitch is given in degrees (°) of inclination.
In sports arenas, rafters are used to drape championship banners.