  This paper describes the most significant data-related challenges involved in
building internet-scale 3D search engines. The discussion centers on the most
pressing data management issues in this domain, including model acquisition,
support for multiple file formats, asset versioning, data integrity errors, the
data lifecycle, intellectual property, and the legality of web crawling. The
paper also discusses numerous issues that fall under the rubric of trustworthy
computing, including privacy, security, inappropriate content, and
copying/remixing of assets. The goal of the paper is to provide an overview of
these general issues, illustrated by empirical data drawn from the internet's
largest operational search engine. While numerous works have been published on
3D information retrieval, this paper is the first to discuss the real-world
challenges that arise in building practical search engines at scale.
