What is the algorithm for
boost::optional< ShadingSurface > addOverhangByProjectionFactor (double projectionFactor, double offsetFraction)
All I can find is the description
Add an overhang to the sub surface, only valid for fixed windows, operable windows, and glass doors. Offset is a fraction of the total window height, projection factor is based on height and offset.
I understand it makes an overhang, but what do the input arguments actually do exactly? I've been unable to find the nitty gritty details anywhere.
