3D Modeling with Paper Published August 31, 2025 Introduction to Paper Modeling (Papercraft) Paper modeling, or papercraft, is the art of creating 3D models by cutting and gluing paper parts. Unlike origami, papercraft allows cutting, gluing, and multiple sheets, enabling more complex yet easier-to-assemble designs. The author shares knowledge gained over years of model building and design. Why Papercraft? Papercraft is: Highly accessible: Requires only paper, scissors, and glue; costs are minimal. Technical and creative: Involves engineering-like problem solving and iterative experimentation. Limitless: Any object can be modeled, limited only by patience and imagination. The featured project is a papercraft model of the SR-71 Blackbird, a legendary reconnaissance plane known for its speed and engineering excellence. --- Constraints in Model Design To ensure ease of assembly and quality, the author sets self-imposed constraints: All parts must be paper. Each part is a single solid color, no textures. The model must be a simple polyhedron — no curvatures or holes; only flat faces sharing edges cleanly. Purpose of Constraints Constraints avoid shortcuts like textures or curved parts which complicate assembly, promote structural soundness, and make the 3D form itself representative of the object. --- Goals Key goals applied throughout design: Ease of assembly – most critical for a good final model. Aesthetic appeal – model should resemble the real object pleasingly. Minimal resource consumption – reduce waste and maximize material efficiency. These goals often conflict and require thoughtful trade-offs. --- Design Process Overview The process is iterative and has three core steps: Mesh modeling – create a 3D polyhedral mesh of the desired shape. Mesh unfolding – flatten the mesh into 2D parts layout for printing. Assembly – cut, fold, and glue parts to build the physical model. --- Mesh Modeling Goals: Ease of assembly & Aesthetic appeal The mesh consists of polygons; more polygons equal more detail but harder assembly. Model complexity balances between a simple low-poly shape and high-res mesh approximating the real plane. Ideal paper model usually has a few hundred polygons. "Allocation of resolution": more polygons assigned to complex features (curves) and fewer to flat ones. Good mesh topology for assembly: Symmetry for intuitive building. Avoid narrow shapes that are hard to cut/fold. Prefer quad faces for aesthetics. Approaches: Easy: Use an existing low-poly mesh from repositories like Thingiverse. Medium: Simplify a high-poly mesh using tools like Meshlab but may result in poor topology. Hard: Create a custom mesh in Blender, offering full control but tedious effort. Author created an initial custom mesh with 732 triangles using Blender, emphasizing symmetry. --- Mesh Unfolding Goals: Ease of assembly & Resource efficiency Convert 3D mesh faces into 2D parts ready for printing and assembly. Use software like Pepakura Designer (Windows, paid), Unfolder for Mac, or Blender’s Paper Model plugin. Auto-unfolding produces complex parts; manual regrouping is required for logical, intuitive parts. Part creation: Logical groupings around features (e.g., engine spikes, nose cone). Mirror paired parts for symmetrical features. Author divided the model into 42 parts. Parts layout: Auto-arranged layouts optimize paper usage but confuse assembly. Manual arranging groups related parts, making assembly easier and saving pages (14 → 12). Flap/tab structure: Flaps enable gluing pairs of edges. Flap placement impacts structural stability. Interlacing flaps across parts creates stronger connections, while same-side flaps are easier to handle. Author prefers interlaced flaps for strength and selective same-side