With the growth in computing, storage, and networking infrastructure, it is becoming feasible for multimedia professionals, such as graphic designers in commercial, manufacturing, scientific, and entertainment areas, to work with 3D models of objects of their interest. As a result, the volume of 3D models available in digital form is rapidly growing. However, we lack a digital library system for these models, where they can be stored, searched and retrieved efficiently. As the size of data representing a 3D model is usually large, it presents a number of challenges in building an efficient digital library system. In this paper, we propose a digital library framework that is designed to provide storage services for 3D models, search and discovery services, and progressive retrieval services. The key to the digital library framework is a representation of a 3D model based on 'surface signatures'. This representation scheme captures the shape information of any free-form surface and encodes it into a 2D image corresponding to a certain point on the surface. The original object can be reconstructed from the intersection of the inverse mapping of few signatures with accuracy that depends on the location of the selected points and the number of signatures used in representing the object. This compressed representation allows for efficient storage and is amenable for progressive retrieval. Also, the 3-D objects can be checked for similarities in the compressed domain.