## 4 Discussion and Conclusions  
The knowledge of seismic behavior of structures has seen significant advancements in recent decades. Still, there is much left to be considered. We are still unfamiliar with a number of things that must be taken into account, such as the magnitude, direction, and scale of earthquakes themselves, as well as their stochastic (random) nature. Some fundamental decisions still need to be made, e.g., whether to opt for deterministic or probabilistic modeling, static or dynamic load modeling, linear or nonlinear seismic behavior of structures. Are we able to minimize the effects of an earthquake, or is optimizing them still the only option? How much do we know about the seismic risk or the potential consequences of seismic activity on our infrastructure? How accurate are we in assessing the seismic vulnerability of existing buildings? Alas, most of these questions remain unanswered as more research needs to be done on seismic risk and seismic vulnerability assessment. Concentrating only on visible issues cannot resolve this questions. Conventional approaches only allow us to assess the condition of an existing structure once its stability has already been compromised. They also only help us when we know from experience that a certain building is vulnerable to seismic activity. But what about any invisible parameters? Are we ready to appropriate new technologies in the engineering sector? Can the use of thermography and UAVs help us expand our abilities in seismic vulnerability assessment? Can any new methods point us to other parameters crucial to the development of this scientific field? How do we precisely characterize data gathered with the help of new technologies? Answering these questions may give way to new principles in the field and foster the use of new technologies of photogrammetry and close-range remote sensing much needed in such a traditional sector as civil engineering. Insight in material and structural properties obtained by assessments and structural analyses and evaluation can help us is in modeling, analyzing, and predicting the performance of existing structures and is always a base for the preparation of the data for more precise analyses. However, it is not always possible to have a comprehensive on-site assessment for rapid evaluation of buildings. The basic idea of this paper is to show the possibilities for the development of an easy and fast procedure for seismically generated damage detection of buildings with new technologies such as UAVs and optical inspections. The open questions and possible future trends in the assessment of the seismic vulnerability of the existing structures is also discussed. The seismic vulnerability of a structure  
Figure 3: Automatic building damage detection and mapping based on the photogrammetric 3D methods and remote sensing techniques. is a quantity associated with its weakness in the case of earthquakes of a given intensity so that the value of this quantity and the knowledge of seismic hazard allows us to evaluate the expected damage from future earthquakes [99]. In modern assessment methods, the seismic vulnerability is represented by vulnerability curves, considering, in individual cases only, some structural characteristics of the affected buildings [100]. Throughout history, a variety of methods have been used to assess the vulnerability that can be divided into empirical and analytical (both approaches can also be used in different hybrid methods) and an approach based on engineering judgment by experts. Methods of vulnerability assessments mainly model damage to a discrete scale of damage commonly using three to six categories [101], but still, there are no unified approaches on a European level. High-definition precision images of buildings using satellites, LiDARs, drones, Google Street View and the like can give us information on floor dimensions, height, floors, etc.