Cellular Automaton Shading for Building Envelopes - Cellular Automata in Image Processing and Geometry - page 201

Table 11.1 A comparison between the functions of skin and building envelope

Function Skin Building envelope

Protection S. is an anatomical barrier from pathogens and dam-

age between the internal and external environment in
bodily defense [43] [36].

Outer shell to protect
the indoor environment.

Sensation S. contains a variety of nerve endings that react to heat

and cold, touch, pressure, vibration, and tissue injury.

Users' sensory con-

tact with the outside

(mostly visual, also

audial).

Heat regula- S. contains a blood supply far greater than its require-

ments which allows precise control of energy loss by
radiation, convection and conduction. Dilated blood
vessels increase perfusion and heat loss, while con-
stricted vessels greatly reduce cutaneous blood flow
and conserve heat.

Temperature control
(insulation, solar gain,
heat

tion

transfer, thermal

mass, etc.)

Evaporation
control

S. provides a relatively dry and semi-impermeable bar-
rier to fluid loss [36].

Moisture control (e.g.

air conditioning)

Storage and S. acts as a storage center for lipids and water. Heat storage (e.g. ther-

mal mass, Trombe wall
[49])

synthesis

Absorption Oxygen, nitrogen and carbon dioxide can diffuse into

the epidermis in small amounts, some animals use s.
for their sole respiration organ [12].

Ventilation (indoor air
quality, hygiene and

public health).

Water resis- S. acts as a water resistant barrier so that essential nu-

trients are not washed out of the body.

Water barrier (water

tance condensation).

Pigmentation Camouflage, mimicry, UV protection, communication,
sexual reproduction, warning etc.

Appearance (aesthetics,
communication).

Structure Other animal coverings such the arthropod exoskele-

ton or the seashell have different developmental origin,
structure and chemical composition.

Structural integrity

(shell).

by the update rules, the same for each cell. This system is therefore homogeneous
like many biological systems [29], and emerging patterns exhibit certain “organic”
integrity as shown in Fig. 11.1.

11.2 Why Cellular Automata to Drive Shading of Building

Envelopes?

CA combine certain properties which are particularly suitable for application on
building facades, as shown in Tab. 11.2. The first property listed there — modularity
is mostly relevant to the fabrication of CASS described in Subsect. 11.6. The CA
modules, although having uniform topology may have various shapes as in the case