OO Model of the STAR offline production "Event Display" and its implementation based on Qt-ROOT

The paper presents the "Event Display" package for the STAR offline production as a special visualization tool to debug the reconstruction code. This can be achieved if an author of the algorithm / code may build his/her own custom Event Display alone from the base software blocks and re-used some well-designed, easy to learn user-friendly patterns. For STAR offline production Event Display ROOT with Qt lower level interface was chosen as the base tools. The paper presents the "Event Display" package for the STAR offline production as a special visualization tool to debug the reconstruction code. 3D visualization has not found for in High Energy Physics research. That essentially represents one or very few events and it can not delivery the information the experiment is designed for. This means the scope of such approach is restricted with: • Debugging the detector geometry • Debugging the simulation, reconstruction and data analysis software codes • Public relations • Rare event evaluations • " Control room " like applications. The list implies the functionality such "Display" application is to be changed as soon as some piece of the instantly evolving code demands the "Event Display" to help finding and recognizing some new problem. The Object-Oriented approach allows creating the reliable OO model and its C++ implementation that is flexible enough to match the oncoming debugging goals. To be useful the working program must be done quickly otherwise the code will be debugged by other means. This can be achieved if an author of the algorithm / code may build his/her own custom Event Display alone from the base software blocks and re-used some good and easy to learn and user-friendly patterns.