A 3D modeling system that provides all-inclusive functionality is generally too demanding for a casual 3D modeler to learn. In recent years, there has been a shift towards developing more approachable systems, with easy-to-learn, intuitive interfaces. However, most modeling systems still employ mouse and keyboard interfaces, despite the ubiquity of tablet devices, and the benefits of multi-touch interfaces applied to 3D modeling. In this paper, we introduce an alternative 3D modeling paradigm for creating developable surfaces, inspired by traditional papercrafting, and implemented as a system designed from the start for a multi-touch tablet. We demonstrate the process of assembling complex 3D scenes from a collection of simpler models, in turn shaped through operations applied to sheets of virtual paper. The modeling and assembling operations mimic familiar, real-world operations performed on paper, allowing users to quickly learn our system with very little guidance. We outline key design decisions made throughout the development process, based on feedback obtained through collaboration with target users. Finally, we include a range of models created in our system.