Sen - R 9717 1997

We present a method for the deenition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and conngure multiple views on his custom 3D interface in an intuitive graphical manner. Each view can be coupled to objects present in the interface, parametrized to (simulation) data, or adjusted through direct manipulation or user deened camera controls. Although our focus is on 3D interfaces for computational steering, we think that the concept is valuable for many other 3D graphics applications as well. 1. INTRODUCTION Computational steering allows a researcher to change parameters of a running simulation and immediately receive feedback on the effect of these changes. As a result, the researcher can gain a much better insight in the behavior of the simulation, he can correct erroneous values for input, and he can steer the simulation into a desired direction. At CWI an environment for computational steering has been developed that allows a researcher to construct and use customized 2D and 3D user interfaces for his simulations. These interfaces consist of both the visualization of the simulation output, and the input widgets that allow the researcher to manipulate the input parameters of the simulation. The definition of the view, i.e. the transformation of 3D scenes to a 2D screen, is a crucial aspect in 3D graphics applications. This is particularly the case in 3D user interfaces for computational steering. First of all, improper viewing of a 3D scene can prevent a good understanding of the 3D scene; important information can be withheld from the user which leads to an incomplete or, even worse, an incorrect interpretation of the scene. Secondly, in computational steering the 3D scene is dynamic. It is not known in advance how the simulation will evolve and therefore it is not known in advance what the 3D scene will look like. This implies that the viewing also must be dynamic and easily reconfigurable. Thirdly, in computational steering applications the user must be able to interact with the scene. Therefore, the user must have an adequate view of the objects to manipulate and be enabled to get good visual feedback of the changes in the scene which result from his actions. And finally, because he creates his own custom 3D user interface to a simulation, the user has control over the layout …