Bohemian Coding Sketch is a true vector editing application and has many powerful tools to manipulate those vectors. Bohemian Coding Sketch has boolean operations that fully preserve your carefully constructed vectors down the individual curves. For optimal flexibility we have something unique; dynamic boolean on groups of vectors. But there is more; Sketch has distortion tools as well as transformations, scissors and your truly innovative Smart Rotate which makes consecutive rotations truly easy and intuitive.
Home Page - http://www.bohemiancoding.com/sketch/