Sardf

Smoothed versions of the intersection and union Boolean functions for implicits.

Reference

@article{fayolle2006constructive,
  title={Constructive heterogeneous object modeling using signed approximate real distance functions},
  author={Fayolle, Pierre-Alain and Pasko, Alexander and Schmitt, Benjamin and Mirenkov, Nikolay},
  journal={Journal of Computing and Information Science in Engineering},
  volume={6},
  number={3},
  year={2005}
}