General comfort can be defined as the measure of the “level of wellbeing” perceived by humans when interacting with a working environment. The state of the art for comfort/discomfort evaluation shows the need for an objective method to evaluate both “effects on the internal body” and “perceived effects” when considering the perception of comfort.Medical studies show that each joint has its own natural resting posture. In this posture, our muscles are completely relaxed or at minimum levels of strain. The body's geometrical configuration corresponds to the natural resting position of arms/legs/neck etc.From this starting point, the authors experimented to develop and built postural-comfort curves for each degree of freedom (DOF) of upper-limb joints. These curves are regular, and do not show any kind of discontinuity. Software (CA-Man®) was developed to analyze different postures and calculate a postural comfort index for the entire upper body.This paper examines a postural comfort study that has been used to develop the MATLAB® Digital Human Model. Several routines for tracing trajectories while reaching for commands in a confined environment (e.g., a work table or a car-cockpit) were evaluated to obtain the maximum perceived postural comfort for each target point. Iso-comfort points were defined for each space, and iso-comfort surfaces were designed using an appropriate CAD system. An example of these routines is shown below.Iso-comfort surfaces can be also customized for different percentiles. This allows car-interior designers to have a virtual knowledge of the final perceived comfort when they decide, for example, on the positioning of a dashboard command.