## 2 Materials and Methods  
To remain competitive, manufacturers are increasingly utilizing CAx systems, such as CAD, to enhance their products. However, it is important to note that neglecting follow-up parts oriented to support CAM systems can hinder the effectiveness of these high-end tools. CAx system manufacturers must also keep up with market developments and continuously improve their software to better meet customer requirements and maintain their position in the market. This trend is expected to continue. The choice of the engine construction node for the creation of visualization and simulation using CAx systems was mainly influenced by an interview with members of the Faculty of Aeronautics, Technical University in Kosice. The Department of Aeronautical Engineering deals mainly with the development of controls for small jet engines. So far, the department has performed all its experiments on a small jet engine, MPM-20, which is located in the laboratory of intelligent control systems of aircraft engines at the Faculty of Aeronautics (Figure 1). As part of the scientific research activity, the laboratory mainly deals with issues of management, diagnostics, safety, efficiency, and reliability of the small jet engine, MPM-20. Various methods and approaches from practice are used to perform experiments--in particular, situation management, artificial intelligence approaches, neural networks, fuzzy systems, expert systems, methods of statistical analysis, probabilistic calculations, and other mathematical methods and models. Based on the requirements of the department and the laboratory of intelligent aircraft engine control systems, it was necessary to create a 3D model of the MPM-20 engine to simplify and streamline current and future experiments. For the digitalization of individual components, CATIA V5 was used as the software basis. CATIA is a 3D design system that can help accelerate the development process of mechanical engineering products. It offers a wide range of solutions that can provide a stable and comprehensive development environment, from design to production. The software provides users with the ability to record and reuse know-how, which drives the implementation of best business practices. The CATIA V5 system comprises three distinct platform configurations, denoted by P1, P2, and P3. These platforms are designed to offer varying options and levels of complexity in terms of available tools. Ascending the platform hierarchy, the range of available options and the sophistication of accompanying tools increase in parallel. The small jet engine, \"MPM-20\" (Figure 2), is a small, single-jet, single-shaft aircraft turbo-compressor engine, which was created by modifying the turbine launcher \"TS-20B\" for the needs of experimental measurements in the aircraft engine test room of the Aviation Faculty in Kosice. The \"MPM-20\" small jet engine has a single-stage radial compressor with a single-sided impeller, a combined combustion chamber, a single-stage axial non-cooled reaction-type gas turbine, and an exit system with a fixed exit nozzle. The \"MPM-20\" engine has a separate fuel-regulating system, oil system, and electric starting system. Figure 1: Laboratory of intelligent control systems of aircraft engines at the Faculty of Aeronautics. Figure 2: MPM-20 jet engine. The small jet engine \"MPM-20\" consists of the following structural elements (Figure 3):  
* Engine inlet (1). * Radial compressor cabinet (2). * Radial compressor (3). * Paddle diffuser (4). * Combustion chamber cabinet (5). * Combustion chamber (6). * Stator ring of a gas turbine (7). * Gas turbine rotor disk with rotor blades (8). * Gas turbine casing (9). For a possible comparison of real components with visualization of the disassembled MPM-20 jet engine, refer to Appendix B, Figure A1. The hand-held 3D scanner EXAscan (Figure 4), which was lent by the company CEIT-KE s.r.o., was used to digitize these components. This hand-held laser scanner allows the quick creation of a 3D CAD model based on a physical object.