Reference paper:
Milroy, M.J., Bradley, C., Vickers, G.W., Segmentation of a wrap-around model using an active contour, Computer-Aided Design, v 29, n 4, 1997, p 299-320
Discussions
One probelm in Last CAd is that models need to be constructed for the large number of existing 'standard' last shapes that are used as a starting point for most new shoe designs. For each style of shoe (e.g. Men's tennis medium), there are standard shope lasts whose shape has been determined over the years by the company, based on their studies of customer comfort, etc. It is easy to scan the exisiting models using a laser scanner, say. The next step is to construct a surface model that will allow easier future shape modifications and other operations (e.g. surface offsets etc.)
This requires skinning or lofting type of operations (that we shall study
later). Also, it is not convenient to build the entire surface into a single
surface -- rather, it helps to segment the data so as to separate the bottom
surface from the top. This is done via mechanisms of segmentation as
discussed in Varady's paper. We shall study a method for segmentation
in more detail to get a flavour for this type operations. Some interesting
related concepts that we shall learn here include:
Energy of a curve in 3D space, and Minimum Strain Energy (MSE) Curves.