We present a new software framework for the development of immersive collaborative virtual reality applications with emphasis on full-body interaction with virtual humans. The framework is designed to be scalable and adaptable to different hardware configurations, using either commodity or more expensive hardware setups. High level programming abstractions handle object replication and communication channels for configurations based on multiple rendering nodes. The system provides tools for full-body character animation, real-time full-body tracking and retargeting to virtual humans, including motion reconstruction from a small set of sensors. Such capabilities allow new full-body interaction metaphors to be developed in fixed or user-perspective stereo visualization. The framework is scalable, customizable, cross-platform and it is only based on tools with source code available.