Dune-UDG: a cut-cell framework for unfitted discontinuous Galerkin methods. Simulations on complex shaped domains are of big interest as the mesh generation for such domains is still an involved process. Recently, cut-cell based methods are becoming very popular. These methods avoid the problems of mesh-generation by using unfitted discretizations on cut-cell meshes. We present the Dune-UDG module which allows an easy implementation of Unfitted Discontinuous Galerkin methods on cut-cell grids. Different geometry representations are available. Using the presented interfaces it is possible to implement completely new cut-cell representations with a minimum of work.