Even if a problem solving method and a domain ontology has been identified, there still remains the problem of adding sufficient and consistent domain knowledge to a knowledge processing system. Our kbVision system supports this knowledge acquisition process by making use of a 3D graphical user interface in which domain objects can be easily created and composed to a domain model. Using object sensitive manipulation options and by evaluating each graphical action in the underlying knowledge representation formalism, the system ensures a consistent domain model. It can also be used as a knowledge-based graphical simulation environment for various reasoning components (e.g. planners, path generators).