The Generalized Finite Element Method (GFEM) is a general framework for approximating partial differential equations enriched by user specified enrichment functions. The starting point of the GFEM method is a partition of unity space composed of hat functions. The enriched space is defined by multiplying each hat function by the set of user defined enrichment functions. The fundamental ideas of the GFEM are documented in \cite{BabuskaMelenk1997,DuarteOden1996,MoesDolbowBelytschko1999}. When applying the GFEM strategy to approximate fractures, two enrichment functions are used: Heaviside functions to represent the discontinuity along the crack face and specially chosen Williams eigenfunctions to represent the singularities around the crack tip. The scaled boundary finite element method is an operator specific method where the extension of a polynomial space on the boundary of a polygonal domain is computed analytically in function of an eigenvalue problem \cite{Song2018SBFEM}. When applied to an isotropic crack problem, the eigenvalues of the decomposition converge to the "classical" eigenvalues of the Williams expansion. In this work we use the SBFEM eigenfunctions/eigenvalues as enrichment functions and as such generalize the applicability of a general purpose GFEM code to configurations where the crack is oriented at an arbitrary angle and/or where the crack exists at the interface of different materials.