In this paper we present a distributed scene graph architecture for use in the blue-c, a novel collaborative immersive virtual environment. We extend the widely used OpenGL Performer toolkit to provide a distributed scene graph maintaining full synchronization down to vertex and texel level. We propose a synchronization scheme including customizable, relaxed locking mechanisms. Our distributed scene graph includes both locally stored nodes for static scene data as well as nodes shared across multiple sites, thus minimizing synchronization overhead. We discuss the performance and demonstrate the functionality of our toolkit with two prototype applications in our high-performance virtual reality and visual simulation environment.