We propose a system called Open3D, that enables collaborative curation of large-scale city models. Users of the system may view the model in the browser (left), which also acts as a social hub. Editing (middle-left) is performed using a novel parametric editing approach that is efficient and intuitive. Changes are applied back to the shared model, taking care to avoid conflicting edits (middle-right) from different users. Operations performed on one model can be retargeted (middle-right) to multiple similar models with a small number of manual adjustments. Note that the color overlays and symbols in the browser (left) are mockups of planned features.

Abstract

Detailed, large-scale 3D models of cities are important assets for many applications. While creating such models is difficult and time consuming, keeping them updated is even more challenging. In comparison, in many domains, crowd-sourcing of data is now an established process for expanding the scope or detail of data sets. In this paper, we describe the initial prototype implementation of Open3D, a crowd-sourcing platform for distributed curation of large-scale city models. We present an open architecture with interfaces that clearly separate model storage and indexing from viewing or editing. To support collaborative editing of extremely large models, we propose to use a modeling and model description paradigm that can integrate polygon-based modeling with parametric operations. We demonstrate the main concepts and prototype through an online city model that can be synchronously edited by multiple users, with live changes being propagated among clients. The main implementation consists of a set of web services, which support key functions such as model storage, locks for editing and spatial queries; a light-weight viewer based on the Cesium library, which runs on desktops and mobile devices; and a prototype editor, which clients can install to edit the models.