The significance of simulation modeling at multiple levels, scales, and perspectives is well recognized. However, existing proposals for developing such models are often application specific. The position advocated in this paper is that generic design principles for specifying and realizing multiresolution, multistage models are still lacking. Requirements for simulation environments that facilitate multiresolution multistage model specification are introduced. A multimodel specification formalism based on graph of models is suggested along with design precepts to enable flexible dynamic model updating. The notion of multisimulation is introduced to enable exploratory simulation using various types of multimodels.