Computational design of structures and materials requires multiscale models to represent geometry and physical properties. In this paper, we propose a multiscale heterogeneous model, dual-Rep, to represent geometry and property distribution implicitly. A new basis function, called surfacelet, is proposed to capture boundary information more efficiently than traditional wavelets. Zoom operations are defined to support multiscale design. A method of materials model reconstruction from images is also developed.Even though multi-resolution geometry representations (e.g., subdivision and wavelets) have been developed, the geometric information is only at the same length scale; from this information, representations at different levels of detail (LOD) can be generated. The major difference between multiscale and multi-resolution modeling is that in a multi-resolution environment, the complete model information is available at the highest resolution, while in multiscale modeling, the highest resolution need not be generated, except when and where it may be needed. For instance, a multiscale model does not require the entire Boeing 787 airplane model to be available at the atomic scale if one component is required at this scale. Instead, in a multiscale environment, it is necessary to render the model at a specified scale when and where a specified region of a model can be rendered at a desired scale for a specific purpose, such as visualization, finite-element analysis, or manufacturing process planning [1].