## 1 Introduction
Because of the importance of user experience, tools, methods, and models are being developed for the \"design for emotion\" approach [15]. The motivation of this study is to provide a solution for the three above mentioned difficulties: the importance of customization, the interdisciplinary knowledge of designers, and the role of emotion in the design. The goal of this research is to examine the connection between appearance and emotions in order to help product designers during the design process. The assumption is that, with the help of the results of this study, designers could create a more aesthetically pleasing design with the focus on geometries, shapes, and patterns on the surface of a product. The consumers' perceived appearance attributes (modernity, simplicity, unity, etc.) have physical properties (such as color, shape, texture, contrast, symmetry) [16]. Figure 2 presents a few examples of a product's physical properties and the perceived attributes. Figure 1: Affective flow. This research is dealing with geometric patterns because, according to literature studies, it can be seen that, while many industries are about to use patterns as an aesthetic feature on a product, only a few of them (for instance, textile industry [17]) use patterns according to their effect on human emotions. For example, in the field of interior decoration [18], jewelry patterns [19], package design [20], textile, and clothing industry [21] research are patterns on products; however, they do not connect them to emotions. In this study, during the pattern development process, only monochrome appearances are applied for patterns, since the technology and the application area which was chosen require only the depth of the pattern. This is why the examination of colors is not part of this paper. The goal is to create patterns based on user preferences. This is why not only a pattern development algorithm is necessary but also investigations, where it was possible to gain information about the consumer's feeling of these patterns. In order to develop an automated pattern generator software, it is essential to examine the existing programs. Pattern generators are used, for example, in web design where the user could create 2D geometric or abstract patterns, or it was also developed in the field of fashion in order to design garments [22], and in architectural design to generate Islamic star patterns [23]. These patterns are mainly working for a specific purpose and textures, but there is no solution to develop general patterns with significant variable elements, and they are not connected to emotions. Because of this lack, the purpose of this study is considered to be appropriate. A collection of a few outputs and interfaces of available pattern generators can be seen in Figure 3.  
Since the existing applications are not capable of 3D projection, a new mathematical method was created for that, which is used in this experimental code called EmPatGen. EmPatGen means Emotional Pattern Generator that creates connections between emotions and geometries. It is an automated pattern development method where the consumers can give emotions and feelings as input parameters and it generates 2D patterns as DXF outputs. The goal is to use this code in the automotive industry, since nowadays, in the automotive industry, the emotion-driven design and the exploration of consumer's specific needs are becoming more and more important [24], which very much fit this goal. The application area of this research is the surface of car interior trim elements. The aim of this system is to help designers create the most aesthetically-pleasing pattern according to the given preferences, applying a new scientific method that connects aesthetic contributions to geometries. Through this software, it is possible to create a unique car interior design  
Figure 2: Examples for product’s physical properties and the perceived attributes. that meets the nowadays more important customizing consumer needs.