In this paper we survey some of the major data structures for encoding Level Of Detail (LOD) models. We classify LOD data structures according to the dimensionality of the basic structural element they represent into point-, triangle-, and tetrahedron-based data structures. Within each class we will review single-level data structures, general data structures for LOD models based on irregular meshes as well as more specialised data structures that assume a certain (semi-) regularity of the data.