The decisions made before the plan
By the time a floor plan exists, the building's character has largely been settled — by which way it faces, what light it receives and what it is built from.
Aspect is the old word for which way a room looks, and it carries more weight than almost any later decision. A south-facing kitchen and a north-facing kitchen are different rooms with different uses, however identically they are drawn.
These notes are about that layer: orientation, daylight and material behaviour, mostly at domestic scale, where the decisions are made quickly and lived with for a long time.
A plan can be revised in an afternoon. Orientation is fixed the day the foundations are set, and every later decision negotiates with it.
Sections
Daylight is about what each orientation actually delivers through the year. Materials covers how surfaces age, which is rarely how they are specified. Drawing is about what representation hides.
Why orientation gets decided badly
Usually because it is settled by something else first: the shape of the plot, the position of the access, a planning constraint, or simply where the previous building stood. None of those are wrong reasons, but they are rarely examined, and a few hours spent testing alternatives at that stage changes the building more than any later effort.