This paper introduces SCIVE, a Simulation Core for   Intelligent   Virtual   Environments.   SCIVE   provides   a Knowledge Representation Layer (KRL) as a central organizing structure. Based on a semantic net, it ties together the  data representations   of   the   various   simulation   modules,   e.g.,   for graphics, physics, audio, haptics or Artificial Intelligence (AI) representations. SCIVE's open architecture allows a seamless integration   and   modification   of   these   modules.   Their   data synchronization is widely customizable to support extensibility and maintainability. Synchronization can be controlled through filters which in turn can be instantiated and parametrized by any of the modules, e.g., the AI component can be used to change an object's behavior to be controlled by the physics instead of the interaction   or   a   keyframemodule.   This   bidirectional   inter module   access  is  mapped  by,  and  routed   through,   the   KRL which semanticall...