I have found AutoCAD to be wonderfully useful for editing patterns for the uniforms that I make for color guard and winterguard. I am able to import a purchased pattern and separate the sizes onto different layers in order to make changes to them before I use a projection system to cut them out. Sometimes I am taking a very basic pattern and making it more complicated, some times I am making a new size that doesn't exist already in the pattern. Any way it goes AutoCAD makes that significantly easier than doing it by hand on paper or in Adobe Illustrator.  I would love to give more detailed views of this and my work flow, but the patterns can't be shared publicly.