Modeling the Effects on Head and Trunk Postures of an Obstruction in the Line of Sight

The main purpose of this study was to investigate and understand the effects of visual obstruction on head and trunk postures, to find by how much these two parts of the body are adjusted to see around an obstruction in the line of sight. At the same time, this study was designed to investigate the same scenario in a JACK simulation and to compare the results. The JACK simulation was validated for the situation in which there is a clear view of a display and for obstructed views where moderate adjustments to posture are needed, but was less realistic when the obstruction was severe and more extreme postural adjustments were required. A possible reason for this is that humans have greater flexibility to adjust shoulder and upper trunk posture than is represented by the digital model. Visual angle to the display and the position of any obstruction in the line of sight were both found to have an important influence on the posture adopted by the viewer, but visual difficulty level was not found to have any significant effect.