At the newly opened Tainan City Museum of Art, Noiz and Kenya Hara co-designed an art installation which links the underground parking space with the ground level, around an oval-shaped staircase. The artwork consisted of an array of vertical louvers with reflective surfaces, intended to translate ever-changing sunlight into a dynamic spatial experience unique to its site, exploring the concept of a 4-dimensional graphic design. The art installation is formed by 3 layers of thin strips of Aluminum plates, arranged in continuously-rotating angles, unique in the way they form an optical device which adjusts the reflective directions of light and brightness of each plate. The installation also respond to the speed and path of movement visually. Louvers set at various angles caused a fluctuation of reflections, a moiré effect that changes based on factors of weather, time and an observer’s movement. While the art installation itself is static, its interaction with sunlight made it possible to experience specific visual patterns. Such interactive effect of the artwork required a highly precise design process, in order to anticipate numerous patterns of movement path and speed, in addition to the moving sunlight. A process made possible with the use of real-time visualization using game engine and 3D-laser scan of the site. The site data was processed with an accuracy with less than 1mm error in every direction, while game engine allowed the design team to verify dynamic visual effects, responding to changes on viewpoint moment and direction of light sources that are impossible to work based on still-rendered images.The project is designed to provide an intriguing experience of emerging from an underground space through a dialogue with one’s own movement and natural light.