Description / Abstract:
SCOPE PURPOSE
This SAE Recommended Practice establishes three alternate
methods for describing and evaluating the truck driver's viewing
environment: the Target Evaluation, the Polar Plot and the
Horizontal Planar Projection. The Target Evaluation describes the
field of view volume around a vehicle, allowing for ray
projections, or other geometrically accurate simulations, that
demonstrate areas visible or non-visible to the driver. The Target
Evaluation method may also be conducted manually, with appropriate
physical layouts, in lieu of CAD methods. The Polar Plot presents
the entire available field of view in an angular format, onto which
items of interest may be plotted, whereas the Horizontal Planar
Projection presents the field of view at a given elevation chosen
for evaluation.
These methods are based on the Three Dimensional Reference
System described in SAE J182a. This document relates to the
driver's exterior visibility environment and was developed for the
heavy truck industry (Class B vehicles, class 6, 7, 8 vehicles)
although the projection principles presented in this document can
be applied to any class of motor vehicles.
This document is intended to complement SAE J1050a and provides
a visual format that can describe the driver's entire viewing
environment. This environment can then be analyzed to determine
what the driver is capable of seeing. It should be noted that one
of the most important factors affecting the driver's field of view
and the ability to make valid vehicle/design comparisons is the
location of the driver's eyepoint. SAE J941 defines the Eyellipse
which forms the basis for eyepoints chosen as the origin for Polar
Plots and Horizontal Planar Projections. The Target Evaluation,
Horizontal Planar Projection and Polar Plot create monocular
evaluations. Projections/plots of multiple eyepoints must be
overlaid to create binocular or ambinocular evaluations.
Analytical methods for creating Target Evaluations, Polar Plots
and Horizontal Planar Projections for direct and indirect vision
(planar and spherical convex mirrors) are presented. Note that it
is possible to create plots and projections for other mirror
surfaces and vision devices if the equations for determining
reflection points are provided.