AICI is VR/AR Library Toolkit for applications running in immersive environments. It provides basic functions to handle all kind of VR/AR relevant input, output devices, multimodal interfaces, 3D user interface, operation handling and multi-threading. The goal of AICI is to let the developer concentrate on their application and let AICI handle the difficulties of VR. AICI focus on keeping flexibility and an architectural integration of all technologies specially required for the evaluation application in the industrial product development process. Here the architecture of AICI and its user interaction concept is presented.