Direct manipulation has proven to be an excellent method for interacting with geometric objects. Unfortunately, traditional approaches for implementing direct manipulation suffer from a lack of generality, requiring the system designer to hand craft interfaces to different types of objects. In this paper we present differential manipulation, a new paradigm for direct manipulation of geometric objects. By interpreting graphical entities as physical objects, we obtain a uniform interface to a wide variety of geometric objects, making it simple to add new types of complicated or compound objects. Geometric constraints fit neatly into the paradigm.

@InProceedings{GW91a,
  author       = "Gleicher, Michael and Witkin, Andrew",
  title        = "Differential Manipulation",
  booktitle    = "Graphics Interface '91",
  pages        = "61--67",
  month        = "jun",
  year         = "1991",
  url          = "http://graphics.cs.wisc.edu/Papers/1991/GW91a"
}