OpenFlipper is an open-source framework for processing and visualization of complex geometric models suitable for software development in both research and commercial applications. In this paper we describe in detail the software architecture which is designed in order to provide a high degree of modularity and adaptability for various purposes. Although OpenFlipper originates in the field of geometry processing, many emerging applications in this domain increasingly rely on immersion technologies. Consequently, the presented software is, unlike most existing VR software frameworks, mainly intended to be used for the content creation and processing of virtual environments while directly providing a variety of immersion techniques. By keeping OpenFlipper’s core as simple as possible and implementing functional components as plugins, the framework’s structure allows for easy extensions, replacements, and bundling. We particularly focus on the description of the integrated rendering pipeline that addresses the requirements of flexible, modern high-end graphics applications. Furthermore we describe how cross-platform unit and smoke testing as well as continuous integration is implemented in order to guarantee that new code revisions remain portable and regression is minimized. OpenFlipper is licensed under the Lesser GNU Public License and available, up to this state, for Linux, Windows, and Mac OSX.