While much research has focused on rendering physically-correct shadows, a “correct” shadow often exhibits unnecessary detail that distracts from the primary subject of the scene. Artists often prefer to have creative control over the rendered appearance of the shadow. This paper presents an algorithm offering control over stylized shadows, based on four intuitive parameters – inflation, brightness, softness, and abstraction – that together support a broad range of effects. The algorithm, which works largely in image space, can easily be incorporated into existing rendering pipelines, and is independent of scene geometry or shadow determination method.

@inproceedings{DeCoro:2007:SS,
   author = "Christopher DeCoro and Forrester Cole and Adam Finkelstein and Szymon
      Rusinkiewicz",
   title = "Stylized Shadows",
   booktitle = "International Symposium on Non-Photorealistic Animation and Rendering
      (NPAR)",
   year = "2007",
   month = aug
}