# A Methodology of Interactive Motion Facades Design through Parametric Strategies
## 2 Background
### Interactive Design  
The design of interactive facades that are mechanical is a potential dynamic solution to environmental and building occupancy concerns. Interactive facades, such as kinetic facades, have evolved from simplified motion to complex responsive systems that respond to the environment; such types of kinetic facades are known as adaptive or responsive facades [12]. Interactive facade design involves more than geometric design solutions, but also a consideration of the constantly changing factors of climate, such as daylight, sky conditions, weather changes, energy saving, and time. Interactive and adaptive facades are part of a field of architecture that focus on the creation of spaces, buildings, or building components that can perform actions that are based on people or the environment through movement, sound, light, wind, humidity, and so forth. While there are various types of functions involved in interactive facades, we have limited this study to the mechanical motion that is involved in interactive facade systems. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Geometry and** & **Energy and Thermal** & **Daylighting** & **Computational Fluid** \\  & **Data Modeling** & **Simulation, Climate** & **Simulation** & **Dynamic Simulation** \\ \hline Main Scope & Create geometrical and data model that support simulation & Predict the impact of architectural design in energy consumption and emissions & Anticipate natural light quality and visual comfort as a function of a space’s geometry and material surfaces & Model airflows inside and outside the buildings, predict comfort \\  & & Ecotect Sun Tool, Ecotect, Vasari (Beta), Climate Consultant, EcoDesigner, ConFeren & Ecotect, Velux & Vasari Wind \\ Design & Revit, Archicad & OpenStudio, EnergyPlus, DesignBuilder, IES-VE, eQuest, TRNSYS & 3 Ds Max, Radiance, Daysim, DIVA & Fluent, Virtual Wind \\ Parametric Design & Grasshopper, Dynamo & JePlus, JePlus EA & Grasshopper and various plug-ins & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: A Survey Parametric Tools in the Architecture Industry and their Function. On a macro level excluding the deformability, flexibility, and elasticity, motions in rigid structures are classified as rotation, translation or a combination of both [13; 14], as seen in Table 2. In the case of linear movement, the translation motion can be defined as the change of position of an object in a parallel space in relation to the coordinated axis, while in the case of rotation, the object changes orientation in space by rotation about the coordinate axis [14]. The case study of buildings in Table 2 shows that the types of motion in rigid structures have been successfully applied to large scale building projects. The rotation motion has been applied to many dynamic skin facades for various functions, including the Keifer Technic Showroom, which used rotation motion for the goal of dynamic solar shading, and One Ocean Thematic Pavilion, for the goal of natural ventilation among many examples. Rotation is a complex motion and the base for other advance types of motion in interactive facades. The scope of the interactive design in this paper focuses on rotation in the interactive facade in the design stage. The comprehension and successful application of motion to facades are conducted through modeling, simulation, and making rapid design iterations in the design phase of the facade. Facade design that involves motion requires being designed differently from conventional building systems, as the facade behaves like a mechanical product. Hence, the modeling process of facades that involve motion requires digital and physical models are complementary to presenting the motion in the facade efficiently. Designers are required to focus on the design activities to enhance productivity due to the complexities in modeling physical and digital models concurrently [15].