  User's perception of product, by essence subjective, is a major topic in
marketing and industrial design. Many methods, based on users' tests, are used
so as to characterise this perception. We are interested in three main methods:
multidimensional scaling, semantic differential method, and preference mapping.
These methods are used to built a perceptual space, in order to position the
new product, to specify requirements by the study of user's preferences, to
evaluate some product attributes, related in particular to style (aesthetic).
These early stages of the design are primordial for a good orientation of the
project. In parallel, virtual reality tools and interfaces are more and more
efficient for suggesting to the user complex feelings, and creating in this way
various levels of perceptions. In this article, we present on an example the
use of multidimensional scaling, semantic differential method and preference
mapping for the subjective assessment of virtual products. These products,
which geometrical form is variable, are defined with a CAD model and are
proposed to the user with a spacemouse and stereoscopic glasses. Advantages and
limitations of such evaluation is next discussed..
