Shadow-scanned human representations for car seat design

Modelling of the human body has a long history as an essential component of computer aided design systems which provide ergonomic analysis of workplaces and equipment. A current Brite-Euram project is concerned with life-cycle aspects of car seating from design through manufacturing and eventual re-cycling. Loughborough University is responsible for driver comfort assessment which is being carried out through road and laboratory trials, the results of which are to be incorporated within the SAMMIE computer aided ergonomics design system. The human body is infinitely variable in shape and dimension and this leads to particular difficulty in generating initial shape representations and subsequently manipulating these to represent individuals or general populations. This paper is principally concerned with a method for capturing shape information and transforming it into a CAD surface representation. The capture method uses a shadow scanning technique where the human body can be scanned in a matter of minutes and ordered coordinate information provided. This information has been processed for input into the DUCT surface modeller where some data reduction can take place before being output in the form of IGES B-Spline surfaces. These surfaces are then processed into a quadrilateral mesh representation that can be handled by the PHIGS functionality implemented within SAMMIE.