Towards a General Model for Selection in Virtual Environments

Selection is one of the fundamental building blocks of all interactive virtual environment systems. Selection is the ability of the user to specify which object, or sub-part of an object in the environment, is the target for subsequent actions. Examples include selecting 3D buttons thus invoking an action or selecting a target upon which an action will occur. Selection is also an implicit or explicit part of manipulation techniques. In a virtual environment selection can be performed in many different ways. In this paper we develop a generalized model of how interaction is and could be performed in virtual environments using 3D gestures. The purpose of this model is to highlight some potential areas for development and evaluation of novel selection techniques. The model is based on an analysis of the complexity of selection. We develop a model for selection that is based on time-varying scalar fields (TVSFs) that encompasses a very broad range of existing techniques. This model will be abstract, in that a direct implementation will be prohibitively complex, but we show how some standard implementation strategies are good approximations to the formal model.