Intra-operative visualization becomes more and more an essential part of medical interventions and provides the surgeon with powerful support for his work. However, a potential deployment in the operation room yields various challenges for the developers. Therefore, companies usually offer highly specialized solutions with limited maintainability and extensibility As novel approach, the CAMPVis software framework implements a modern video game engine architecture to provide an infrastructure that can be used for both research purposes and end-user solutions. It is focused on real-time processing and fusion of multi-modal medical data and its visualization. The fusion of multiple modalities (such as CT, MRI, ultrasound, etc.) is the essential step to effectively improve and support the clinician's workflow. Furthermore, CAMPVis provides a library of various algorithms for preprocessing and visualization that can be used and combined in a straight-forward way. This boosts cooperation and synergy effects between different developers and the reusability of developed solutions.