Collaborative 3D Modeling by the Crowd

We propose a collaborative 3D modeling system that deconstructs the complex 3D modeling process into a collection of simple tasks to be executed by nonprofessional crowd workers. Given a 2D image showing a target object, each crowd worker is directed to draw a simple sketch representing an orthographic view of the object, using their visual cognition and real-world knowledge. The system then synthesizes a 3D model by integrating the geometrical information obtained from a collection of gathered sketches. We show a set of algorithms that generates clean line drawings and a 3D model from a collection of incomplete sketches containing a considerable amount of errors and inconsistencies. We also discuss a crowdsourcing workflow that iteratively improves the quality of submitted sketches. It introduces competition between workers using extra rewards based on peer-reviewing as well as an example-sharing mechanism to help workers understand the task requirements and quality standards. The proposed system can produce decent-quality 3D geometries of various objects within a few hours.