A geometrically based flattening method for three-dimensional to two-dimensional bra pattern conversion

This article proposes a robust algorithm for three-dimensional (3D) surface reconstruction of a bra fitted to an underlying mannequin via scanned polylines and a novel approach for bra pattern flattening based on linear least squares optimisation. This pattern flattening method projects a patch from the current viewing direction to a two-dimensional (2D) plane, with an orientation into 3D space by mesh reconstruction. The intersection of polylines is checked and a patch adjacency graph is built to form a closed patch surface, which is fitted to a mannequin. The conformity between the 3D bra patch and the 2D projection shows shape preservation when the 3D bra is flattened to 2D patterns using the proposed method. The preservations of shape entities include boundary coordinate preservation, mean value coordinate preservation, edge length preservation and adjacent surface flattening. An algorithm for calculating the local projection plane, which is used for the calculation of best fit mean value coordinate for local surface flattening, is also provided.