INTERACTIVE GRAPHICS PACKAGE FOR CALCULATING CROSS-SECTIONAL PROPERTIES OF COMPLEX SHAPES

The cross-sectional properties of complex shapes are required in many studies of musculoskeletal biomechanics. This note provides an interactive computer graphics software package for calculating the area cross-sectional properties of irregular, two-dimensional shapes. The program requires input of the boundary coordinates of multiple, planar regions, each of which may be multiply connected. The program then calculates the area, centroid, area moments of inertia, and principal moments and their orientations. The approach thus allows rapid analysis of the section properties of complex biological cross-sections and facilitates both the mechanical analysis of musculoskeletal components and the quantification of biological changes in cross-sectional geometry due to aging, metabolic bone disease, or the presence of an internal fixation device. The basic algorithm used for these calculations is described and the FORTRAN implementation of the technique is outlined. Examples of the application of the method are then discussed.