The research is structured around complex optical effects of undulated glass and coatings that exhibit high reflectivity, especially at higher incidence angles. This optical behavior allows great directional and intensity variation even with minimal curvatures. This is especially visible in undulated glass facades, where the ratio of reflection and transmission changes dramatically with every change of viewing angle, producing dynamic effects. Furthermore, caustic and dispersion light effects may additionally enrich the visual architectural language. However, high-frequency and high-amplitude curvatures also create optical distortion and lens effects, thus producing undesirable glare and potential overheating. Therefore, these undulated glass geometries require special consideration and analyses during the design phase to maximize their optical benefits and reduce unwanted side-effects.
The research explores self-shading potential and optical benefits of undulated glass geometries through modulating surface curvature. Sinusoidal functions are used to define coherent procedural glass surface curvature with variable amplitude values. Due to the high directional sensitivity, virtual prototyping of undulated geometries was performed with a high temporal and spatial resolution and assuming the most common vertical setting.
Optical benefits are presented through g-value and daylighting metrics for a set of undulated glass facade states, varying curvature amplitude, and directionality. The results indicate moderate self-shading potential and daylighting benefit of undulated glass facades. The research findings aimed to provide a valuable resource for articulating design and performance aspects of undulated glass facades, potentially reducing the need for additional shading and daylight-redirect elements.
Undulated glass facades
Since the introduction of glass in architecture, there has been significant progress in technology that made possible glass performance and size improvements. Nowadays, technologies such as thin glass
The methodology of the paper is based on the computational framework that defines the undulated glass façade system through a set of parameters controlling surface curvature. A computational workflow is
The results of experiment 1 are shown in Figure 7. The table shows g-values for both extreme states, planar and fully curved, plus five interpolation states. In total there are
Given the experiments’ results, it can be concluded that undulated shading have multiple optical benefits. Firstly, figurated geometry of the glass surface can reduce g-value by up to 10% under
 L. Galuppi and G. Royer-Carfagni, “Optimal cold bending of laminated glass,” Int. J. Solids Struct., vol. 67–68, pp. 231–243, Aug. 2015.
 T. Kiser et al., “Architectural Caustics-Controlling Light with Geometry,” in Proceedings of the Advances in Architectural Geometry Conference, 2012.
 L. Maierova, A. Borisuit, J.-L. Scartezzini, S. M. Jaeggi, C. Schmidt, and M. Münch, “Diurnal variations of hormonal secretion, alertness and cognition in extreme chronotypes under different lighting conditions,” Sci. Rep., vol. 6, no. 1, p. 33591, Dec. 2016.
 Jakica Nebojsa and Zanelli Alessandra, “Dynamic Visualization of Optical and Energy Yield Co-Simulation of New Generation BIPV Envelope in Early Design Phase Using Custom Ray Tracing Algorithm in Python,” in Proceedings of Advanced Building Skins Conference, 2014.
 S. Rockcastle and M. Andersen, “HUMAN PERCEPTIONS OF DAYLIGHT COMPOSITION IN ARCHITECTURE: A PRELIMINARY STUDY TO COMPARE QUANTITATIVE CONTRAST MEASURES WITH SUBJECTIVE USER ASSESSMENTS IN HDR RENDERINGS,” in 14th Conference of International Building Performance Simulation Association, 2015.
 N. Jakica and A. Zanelli, “Innovative Cable Net Curved-Glass Photovoltaic Facade,” Interfaces Archit. Eng. Sci., no. September, pp. 1–7, 2017.
 C. F. Reinhart, J. A. Jakubiec, and D. Ibarra, “DEFINITION OF A REFERENCE OFFICE FOR STANDARDIZED EVALUATIONS OF DYNAMIC FAÇADE AND LIGHTING TECHNOLOGIES 1 Massachusetts Institute of Technology , Cambridge , MA 02139 , USA 2 Harvard University , Graduate School of Design , Cambridge , MA 02138 , USA,” 13th Conf. Int. Build. Perform. Simul. Assoc., pp. 3645–3652, 2013.
 G. and S. R. Ward, “Rendering with Radiance: The Art and Science of Lighting Visualization,” Morgan Kaufman, 1998.
 C. F. Reinhart and O. Walkenhorst, “Dynamic RADIANCE-based Daylight Simulations for a full-scale Test Office with outer Venetian Blinds,” Energy Build., vol. 33, no. 7, pp. 683–697, 2001.
 Illuminating Engineering society, IES spatial daylight autonomy (sDA)and annual sunlight exposure (ASE). IES, 2013.