Draft3D: An open-source local software platform for sketch-conditioned multi-stage 2D-to-3D concept generation

Sketch-conditioned 2D-to-3D concept generation is useful for early-stage visual concept exploration in product-design research. Compared with single-stage generation, multi-stage workflows allow users to inspect intermediate 2D results, compare candidate concepts, and perform stage-wise refinement before 3D reconstruction. However, such workflows also introduce higher barriers to implementation and deployment because users often need to manually coordinate multiple models, scripts, and node-based workflows. This paper presents Draft3D, an open-source local software platform for sketch-conditioned multi-stage 2D-to-3D concept generation. The platform integrates raster sketch input, 2D candidate image generation, prompt-based editing of intermediate 2D results, and 3D mesh reconstruction into a unified graphical workflow. Draft3D is intended for early-stage concept exploration rather than production-ready CAD modeling, part-level segmentation, or direct geometric editing of reconstructed 3D meshes. Representative examples across multiple product categories are used to illustrate the end-to-end workflow of the platform. Minimal reproducible examples and preliminary usage cases are further provided to offer an initial indication of its usability and applicability in design research scenarios.