A method and apparatus enables direct manipulation of 3D curve images on a computer display. In accordance with this method and apparatus, a curve object is created which, in turn, generates a 3D virtual box image enclosing a portion of a selected curve image. The 3D virtual box image has areas which...http://www.google.com.au/patents/US5583977?utm_source=gb-gplus-sharePatent US5583977 - Object-oriented curve manipulation system
