We present a novel method for procedurally modeling large complex shapes. Our approach is general-purpose and takes as input any 3D polyhedral model provided by a user. The algorithm exploits the connectivity between the adjacent boundary features of the input model and computes an output model that has similar connected features and resembles the input. No additional user input is needed to guide the model generation and the algorithm proceeds automatically. In practice, our algorithm is simple to implement and can generate a variety of complex shapes representing buildings, landscapes, and 3D fractal shapes in a few minutes.