Green walls reduce building energy as well as improve environmental health conditions such as water quality and air quality. While green walls have many benefits, a significant drawback is the cost of additional materials such as structural systems and irrigation. A B.I.G. Wall would reduce the cost of a green wall by passively encouraging moss growth without additional structural support or extensive irrigation system. Daylight, water flow, and manufacturing analysis, form generation, and optimization algorithms control a surface orientation, water shedding ability, and machining requirements for fabricating the digital form.