Polygonal Models are ubiquitous in every application of Computer Graphics but their real time manipulation and rendering in such interactive application environments as are sensitive to their sizes and complexity have become a threat. A whole family of automatic algorithms emerged during the last decade to help out this problem, but they reduce the complexity of the models uniformly without caring about semantic importance of localized parts of a mesh. Only a few algorithms deal with adaptive simplification of polygonal models. We propose a new unified framework for user-driven simplification exploiting the simplification hierarchy and hypertriangulation model, which lends a user the most of the functionalities of existing adaptive simplification algorithms in one place. The proposed new underlying data structures are compact and support real time navigation across continuous LODs of a model. Comparison with related work shows that the proposed framework provides combined environment at reduced overhead of memory space usage and faster running times.