### Iconic Road Bridge design optimization

Design Optimization is a complex task, because involves design criteria and iterative decisions over the same problem until some condition is met. The optimization process involves a series of constraints related to costs, fabrication and aesthetics. The correct use of mathematics (Linear algebra, geometry, arithmetic, etc) in the right time is essential to converge in a successful result to avoid fall in an infinite loop. The result, needs to be measurable with high precision and it needs to be quantifiable in order to transform the data into information (plans and documentation).

Working at IDOM in 2013, I had the chance to work in a facade design-optimization for the Abi Bakr Road Bridge. The project was designed and developed 100% using Rhinoscript. The design and development was a collective effort between architectural and engineering departments at IDOM Barcelona.Design is an abstract process of organization that involves composition and evaluation. A good design is a subtle well balance of the elements in the system to organize. In this post I will not go through the design process but discuss the optimization process.

##### Optimization

An optimization process, needs to be described as quantifiable steps. Because is necessary to evaluate every step in the process and also the possibility to evaluate any adjacent element in the process. For example the cumulative gap tolerance among all panels. An optimization process also needs a target or stop condition which is essential to determine the path to set up the steps. for this project the target was to minimize the number of different facade panels in order to find the wright balance between design and rational budget.

##### The Optimization Process was divided in three main steps:

Step 1: Design and understand structural geometry
Print all different angles from the existent design. Because the facade works as a wrapper of the structure and it was defined by 3 curves.

Step 2: Reduce the number of different angles but keeping the original design
The bridge is not symmetric in terms of elevation, therefore the angle of the structures varies from one structural frame to another. Therefore the facade performs as a double curvature surface. A subroutine was created to round the angles and redraw the existent profile again, with the smallest visual difference. At the end of the step we obtain a smooth curve composed by no more than 15 angles to wrap the structure.

Step 3: Evaluate step 2 and check distance to structure
Check each curve segment is under the structural distance tolerance (dt) is 200 mm <= dt <= 500 mm. Some curves are deleted and replaced by equal segments in order to reduce the number of angles. At the end of the process we obtain a smooth curve composed by only 11 angles. In almost each case the angle change each 3 modules, which implies simple clues to mount and fabricate. The result is expressed in a diagram of angles as a phenotype of the design.

Envelope Generation
The optimization process is documented trough scripting.

Pattern Generation
The patterns was designed based in a series of attractor points, which affect size and density. The area of points was control trough an equation which is often used to describe stocks and markets in business.