Beyond user experimentation: notational-based systematic evaluation of interaction techniques in virtual reality environments

Abstract

Despite the increasing number of interaction devices for virtual reality (VR) applications (e.g. data-gloves, space balls, data-suits and so on), surprisingly very little attention has been given to the evaluation of VR interaction techniques or more generally to the usability of virtual reality environments (VRE). The main reasons for these limited efforts are probably that empirical user testing with VREs is difficult and time-consuming and ergonomic rules or criteria and traditional HCI tools and methods are not well suited for VRE. Alternatively, the specification of interaction based on a formal method or notation provides a precise and unambiguous description that can be used to reason the user’s actions while interacting with a VRE. In this paper, we propose a new approach to design interaction techniques in VRE, based on the use of a formal specification language: the ASUR notation. In the early stages of system design, time and effort are reduced by assisting the designers in considering alternative solutions and anticipating usability issues. To better explain the proposed methodology, we report an evaluation of selection and manipulation techniques in a virtual environment based on a chess game. The evaluation has been carried out in two ways: predictively, with the help of the ASUR notation, and empirically via user experiments. We present the outcomes of the empirical studies and demonstrate that the reasoning with the ASUR notation leads to similar but also results complementary to those obtained with the experiments.