We present a method for procedurally modeling general complex 3D shapes. Our approach is targeted towards applications in digital entertainment and gaming and can automatically generate complex models of buildings, man-made structures, or urban datasets in a few minutes based on user-defined inputs. The algorithm attempts to generate results that resemble a user-defined input model and that satisfy various dimensional, geometric, and algebraic constraints. These constraints are used to capture the intent of the user and generate shapes that look more natural. We also describe efficient techniques to handle complex shapes and demonstrate their performance on many different types of models. CR Categories: I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling—;