  Numerical models and computer-aided modeling software are tools commonly used
to assess the accessibility of an environment, based on static human body
dimensions. In this paper, the limits of validity of these approaches are
assessed by comparing the reach envelopes obtained by these methods to those
obtained experimentally. First, the accessibility areas of forty adult
subjects, which may correspond to the distance of reachability of products,
were evaluated by performing an accessibility task comprising 168 reach points.
Second, anthropometric characteristics of participants were recorded and used
to perform the reach assessment by a numerical method, and then by a CAD-based
analysis, where the reach was predicted using the software's maximum
reach-envelope generation. In spite of the simple nature of the presented
design problem (two-dimensional), the results show important differences
between the three methods. The study of the number of reached points shows that
the CAD-based assessment provides more accurate results than the numerical
model. Nevertheless, the shapes envelopes comparison indicates that the maximum
reach envelopes obtained with the CAD analysis are not always consistent with
those obtained experimentally, closely linked to the hand location. Results
indicate that the CAD model used to obtain maximum reaches gave predictions
that underestimate the reach ability.
