The Use of Physical Props in Motion Capture Studies

It is generally accepted that all postures obtained from motion capture technology are realistic and accurate. Physical props are used to enable a subject to interact more realistically within a given virtual environment, yet, there is little data or guidance in the literature characterizing the use of such physical props in motion capture studies and how these effect the accuracy of postures captured. This study was designed to evaluate the effects of various levels of physical prop complexity on the motion-capture of a wide variety of automotive assembly tasks. Twenty-three subjects participated in the study, completing twelve common assembly tasks which were mocked up in a lab environment. There were 3 separate conditions of physical props: Crude, Buck, and Real. The Crude condition provided very basic props, or no props at all, while the Buck condition was a more elaborate attempt to provide detailed props. Lastly, the Real condition included real vehicle sections and real parts. Plant operator subjects were also provided video feedback of themselves performing the task in the actual assembly plant, to ensure a similar method was used in the lab. Analyses of the postures adopted for each of prop levels indicate that there are differences associated with each. Relative to the motion capture using real automotive parts, there were marginal differences as the assessment progressed from crude to more complicated physical props.