# Virtual Scene Construction for Seismic Damage of Building Ceilings and Furniture
## 1 Introduction
For problem 2, the FEMA P-58 guidelines provide criteria for determining the DSs of nonstructural components. Establishing such criteria is challenging because numerous experiments and simulations are necessary. The Federal Emergency Management Agency (FEMA) of the United States proposed the FEMA P-58 method after a 10-year effort [21; 22]. FEMA P-58 is a state-of-the-art seismic performance assessment method for structural and nonstructural components. As FEMA P-58 contains a wide range of fragility curves, it has been used extensively for predicting the seismic performance of indoor nonstructural components. Specifically, structural THAs can provide the required engineering demand parameters (EDPs) for the fragility curves, such as the inter-story drift ratio (IDR) and peak floor acceleration (PFA). Subsequently, by employing the fragility curves in FEMA P-58, the probabilities of nonstructural components experiencing different seismic DSs can be determined. With respect to problem 3, a physics engine can provide an appropriate simulation platform. Physics engines are computer codes that specialize in calculating the complex physical behaviors (e.g., multi-body dynamics) of objects with high efficiency [23]. Currently, Havok [24], Bullet [25], and PhysX [26] are the three most popular physics engines, and these are widely used for motion simulations in the VR field [27]. For instance, [PERSON] et al. [28] employed PhysX to simulate the movement of debris during a bridge collapse. Therefore, a physics engine can be also employed to simulate the subsequent movements of damaged nonstructural components. In addition to simulation platforms, a physical model considering the specific seismic responses and DSs of nonstructural is also needed for the above simulations. For instance, the seismic acceleration and velocity will affect the movement of furniture, while the number of falling objects will differsdepending on the DS of the ceiling. Therefore, a valid physical model on the subsequent movements of damaged nonstructural components deserves further studies. In this study, suspended ceilings and moveable furniture are the primary focus. A virtual scene construction method for the seismic damage of suspended ceilings and moveable furniture is proposed based on FEMA P-58 and a physics engine. First, a BIM-based modeling framework is designed to create consistent structural and scene models used for the structural THA and scene construction. FEMA P-58 is then employed to determine the DSs of nonstructural components based on the results of the THA. Finally, the physical models on the movements of the damaged components are designed using a physics engine and are also validated through the experiments such as an existing shaking table test. Taking a six-story building as a case study, a virtual seismic damage scene of the indoor nonstructural components is constructed and applied in an earthquake safety drill. The outcome of this study provides well-founded scenes of the seismic damage to indoor nonstructural components for performing virtual earthquake safety drills.