Digital Definition of the Deflected Shape of the Human Body in Seated Postures for Ergonomic Design in CAD Models
An advanced biofidelic shape of the human body is needed in computer-aided design (CAD) models for ergonomic design. To be used in seat and automotive design, this advance in biofidelity must be a 3D CAD tool that includes the deflected shape of the human body and must include skeletal landmarks, especially those related to load paths. The CAD tools must represent the range of the population and must also represent the full range of seated postures. To develop our CAD models, a 3D anthropometric study was undertaken that used skeletal landmarks to define relative positions of transverse cross-sections that describe both the “visible” and “invisible” shape of the seated body. Data were collected on large males, average males and small females. Subjects were measured in several postures while sitting on flat foam pads. Transverse sections were measured at the center of gravity of each thigh, under the ischial tuberosities and at the S2, L4, T8 and T4 spinal levels.