The Simplicial Multi-Complex (SMC) is a general multiresolution model for representing k -dimensional spatial objects through simplicial complexes. An SMC integrates several alternative representations of an object and offers simple methods for handling representations at variable resolution efficiently, thus providing a basis for the development of applications that need to manage the level-of-detail of complex objects. In this paper, we present general query operations on such models, we describe and classify alternative data structures for encoding an SMC, and we discuss the cost and performance of such structures.