Virtual reality in assembly simulation: collision detection, simulation algorithms, and interaction techniques

interface to a number of input devices. This layer is used mostly by the VEMS. I will describe it in more detail in Section 4.1.1. Close to the object handler is the collision detection module (see Chapter 3). It is responsible for detecting collisions among objects in the scene graph. In my implementation, it is integrated in the object handler, so that it notices automatically when objects have moved. This module is used mostly by physicallybased simulation modules and by the interaction handler. Plug-ins are modules which provide some application-specific behavior or functionality, or an on-line interface to other applications such as CAD systems. They can be loaded at run-time by the VR system. Almost all modules should be able to run concurrently to each other. This is particularly necessary for real-time critical modules such as the renderer, physically-based simulation, and collision detection module. In our VR system, the renderer, collision detection, device drivers, and wind tunnel simulation modules can run concurrently, as well as some of the physically-based modules. Of the modules described so far, I have implemented the interaction manager (VEMS), the collision detection module, and the device layer and drivers, in addition to some physically-based simulation and several plug-ins for many applications.