  A common operation performed in Virtual Reality (VR) environments is
locomotion. Although real walking can represent a natural and intuitive way to
manage displacements in such environments, its use is generally limited by the
size of the area tracked by the VR system (typically, the size of a room) or
requires expensive technologies to cover particularly extended settings. A
number of approaches have been proposed to enable effective explorations in VR,
each characterized by different hardware requirements and costs, and capable to
provide different levels of usability and performance. However, the lack of a
well-defined methodology for assessing and comparing available approaches makes
it difficult to identify, among the various alternatives, the best solutions
for selected application domains. To deal with this issue, this paper
introduces a novel evaluation testbed which, by building on the outcomes of
many separate works reported in the literature, aims to support a comprehensive
analysis of the considered design space. An experimental protocol for
collecting objective and subjective measures is proposed, together with a
scoring system able to rank locomotion approaches based on a weighted set of
requirements. Testbed usage is illustrated in a use case requesting to select
the technique to adopt in a given application scenario.
