Evolutionary Strategy:To optimize the structure performance in regards to environmental performance, a series of sequential design research was done in regards to sunlight Filtering and Aerodynamics. The first parameter to consider was the irradiated surface area, to achieve a higher sun-coverage. In other words, the first step was to generate a surface that should show a high exposure to sun, in order to cover as much as possible and not concentrate the exposed area in one single point.
The second parameter was the shadow_casting, as the temperatures rise over 35 degrees almost all year long, shade is needed to enhance the space quality.
An evolutionary strategy was set up as a design approach as design should depend on different variables, being Sunlight filtering and Shadow casting one of the External pressures that will determine the overall performance in a highly sun-exposed and strong wind gusts scenario.
As the shape is intended to be an architectural structure, shadow casting is also proposed as a final purpose for selection.
“Genome is addressed as a code that is related to a specific phenotype which makes each morphology as part of the same specie, sharing a similar genetic code. This means that all the shapes from specific populations (determined by iterations) are topologically similar but geometrically variant”.
In order to define the phenotype based on sunlight performance, shadow casting is taken into account. As mentioned before the climate conditions of the Atacama Desert are quite hostile for almost every living organism, as the sunlight intensity and temperatures can be extremely high, leading to a subsequently lack of vegetation which leaves the whole terrain exposed to sunlight.UV rays filtering is necessary as well as shading in order to decrease the temperatures during daytime and allow human inhabitation. Three morphologies, product of the previous design-evolution-strategy, are studied in terms of shadow casting; considering the summer and Winter Solstice as the main references to study shadow casting, as these are the margins that define the sun trajectory.
SA_1: is a symmetric shell whose best performance can be clearly seen from 12:00 to 13:00 pm on all seasons but the relation between covered space and shaded area is not good as the shadow from 14:00pm onwards is cast ‘outside’ the covered space, exposing the shaded area to other climatic conditions.
SA_2: behaves in a similar way as the previous phenotype but has a better coverage as there is differentiation between the area that is directly exposed to the sunlight direction (north) ant the unexposed area.
SA_3: Is a totally differentiated shape oriented in an angle that follows the sun trajectory. The reduction in height and the orientation change leaves a proportional covered and shaded space throughout most of the year where the only exposed-shaded space occurs at 16:00pm on winter.A E R O D Y N A M I C P H E N O T Y P E :
The design process that generates the overall morphology of the surface is proposed as a responsive evolutionary morphogenesis where extrinsic pressures such as wind flow and sunlight should inform the final design, just as it occurs in natural systems, where design is a consequence of an evolutionary process of adaptation to extrinsic forces, where mutations under sequential iterations are the base for adaptation and survival.
The first “parent” or phenome (Sa_c1), is a simple 4-points surface, with both flat and curved zones. The idea was to propose a simple surface as the first parent that should mutate to achieve a higher degree of complexity, always related to aerodynamic performance. Each mutation is addressed with a genotypic syntax that is related directly with a particular phenome, which puts the design into an evolutionary context where a specific genome can be used to generate a new population or design series.
Sc1(Single-curved surface): is a basic aerodynamic shape where wind gets deflected generating a lower pressure area on the top of the curved surface that accelerates the wind flow avoiding turbulence; following the Bernoulli principle.
Sc2(Double-curved surface): Consists basically in one mutation that adds a negative curve to the surface at it’s maximum-height point (the centre of the surface). Higher velocity in the negative curve area is produced reducing the wind velocity in the remaining areas of the surface. It can be said that wind acceleration is parametrically and topologically controlled.
Sc2_O(Double-curved perforated surface):
Taking advantage of the low-pressure (high velocity) area, the surface is perforated in order to conduct the direction of the wind that eventually flows towards the perforation ventilating the inferior part of the surface. The wind is not only deflected by the remaining areas of the surface but also is manipulated in order to ventilate and cool-down the dwelling space.
F I N A L P H E N O T Y P E : Environmental Responsive Surface
The Final Structure Morphology is a product of a combination of performantive properties taken from the Sunlight-Covering-Shell phenotype and the Aerodynamic-Surface phenotype; which in other words, is a product of the genotypic combination of two different morphologies generated under two environmental pressures that defined the fitness criteria.
The outcome of this combination is a shell that is designed both under the sunlight covering criterion and the aerodynamic criterion related specifically to the location of the project. We can argue that this design process (taking extrinsic factors like location, and environmental pressures as a fitness criteria to define the final design) is a responsive process as it is defined by the adaptation to different environmental pressures inherent to the place where the project is designed and the final design emerges from a combination of external factors and the material’s inherent behaviour and properties, resulting in a longer lasting design and a coherent negotiation with the place where it is located.
The structural performance of the pavilion has to deal with a synergetic relation between a Meso and a Micro scale, where overall geometry determined by parabolic and negative curves have a specific structural performance, but structural reinforcement is needed in different areas along the surface, hence, differentiation at a local or Micro scale is needed.After analysing the structural performance of the spine formations, we decided to use them as a structural component, and differentiate their distribution along the surface according to structural needs.As it can be clearly seen on the Strain analysis, the maximum strain is concentrated on the southern part of the shell, so we decided to generate a more dense area in order to reinforce the shell.
Differentiation is defined by structural performance where hierarchies emerge from a different distribution of the component (spine formations).
Sunlight Filtering Differentiation:
On the Meso-Scale, the overall morphology of the shell is intended to generate a shelter from the intense solar rays and cast a continuous and extense shadow area throughout the year, but in a Local Scale, the components can act as sunlight filters.Due to the inherent translucency of the material used on this project, an overall Sun-covering shape at a Meso Scale is not enough; hence we decided to produce differentiation in the distribution of the spine formations, just as it was done according to structural performance, in order to generate different-density areas, that would generate a higher sunlight filtering (and cast a denser shadow) where needed or more translucent areas where the sunlight effect is less relevant.
Rather than an absolute sunlight-covering shape at a Meso Scale, Hierarchies are proposed at a micro-scale, where differentiated density areas filter the sunlight according to local environmental performance.
“Genotype: is the internally coded, inheritable information carried by an individual; in other words it is the specific genetic makeup. Together with the environmental variation that influences the individual, it codes for the phenotype or physical manifestation of that individual.”
A responsive design process is proposed by focusing on a strategic combination of isolated inductive approaches, where external environmental pressures would define a phenotype or the physical manifestation of the project and it’s performance under the specific location.
Previous studies such as form-finding and biomimetics are used as genotypes, or the genetical information that would configure the final design, where environmental pressures act as the fitness criteria that would define the pavilion’s morphology.
Form Finding: defines not only the material approach, but also the structural performance of self-optimised morphologies that can be used as a component, and that are the main study of our research.
Shells: Built references will inform both geometric and performative design strategies.
Biomimetics: is referred to optimised-differentiated structures present in nature, especially on cancellous bone tissues and bird skulls. Strength to weight ratio and heterogeneity found on cancellous bone tissues are the main structural and morphological inspiration that informs the final design at a micro level.
C O M P O N E N T D I F F E R E N T I A T I O N: OPTIMISATION FROM MICRO TO MACRO LEVELS.