Historical Post 2 - September 2007 : Breakthrough - External Straight Skeleton Nodes OK , not much of a catchy title. However, if you've been reading about the issues I've been having with calculating external straight skeletons, you may know a little about what I'm talking about. After some time spent scratching my head, walking away from the problem and a fair bit of frustration (OK, a lot), it's time for an update. To recap, straight skeletons are useful data structures for calculating the offset path for a (simple) polygon. They are also used for calculating roof structures. Most of the material I've found on the web seems to be concerned with calculating internal skeletons, although no distinction is usually made between the two types. To be able to expand polygonal paths I need to be able to calculate external skeletons. Unfortunately, I've found that these are less frequently discussed and appear to have features that you don't encounter...