Guest Editors' Introduction: 3D Documents

Digital libraries (DLs) in general and technical or cultural preservation applications in particular offer a rich set of multimedia objects like audio, music, images, videos, and also 3D models. However, instead of handling these objects consistently as regular documents - in the same way we treat textual documents - most applications handle them differently. Considering that textual documents are only one media type among many, it's clear that this type of document is handled quite specially. A full-text search engine lets users retrieve a specific document based on its content - that is, one or more words that appear in it. Content-based retrieval of other media types is an active research area, and in the case of 3D documents, only pilot applications exist.