In virtual environment (VE) various type of interaction can be used. Typical task in VE is a manipulation with virtual objects. Each VE task can be realized in different manners. Direct manipulation in three dimensions is difficult when we are limited by 2D conventional graphical interfaces such as mouse or tablet.
One of the reasons that makes human-computer interaction (HCI) in VE so laborious, is that user has no haptic contact with objects situated in virtual world. This imperfection causes problems particularly in cases when we access VE using a real-world metaphor. In real world users can touch only objects that are within the reach of their arms.
Therefore we seek interaction techniques, which help us to interact in VE applications correctly, rapidly and without unnatural limitations. Most of these techniques fall in four categories:
In subsequent sections we will describe individual ways of adduced types of interaction which ease work within VE. We will review user interfaces that are used for interaction with virtual reality. Especially, we will aim at various kinds of trackers and devices for visual and force feedback.