A 2D sketch interface for a 3D model search engine

This sketch describes our experiences with creating query interfaces for an online search engine for 3D models. With the advent of affordable powerful 3D graphics hardware, and the improvement of model acquisition methods, an increasing number of 3D models is available on the web, creating a need for a 3D model search engine [Paquet and Rioux 2000; Suzuki 2001]. An important problem that arises for such an application is how to create an effective query interface. To investigate this issue, we created several different query interfaces, and tested them both in controlled experiments as well as in a publicly available 3D model search engine. Perhaps the simplest approach to search for 3D models is to match keywords in filenames, captions, or referring webpages. However, trying to find 3D models just using text-based search techniques is not always effective: model files may be insufficiently annotated (e.g. pr122.dxf, john.wrl, misspellings, foreign languages), or ambiguously annotated (e.g. plane.wrl). In these cases and others, we hypothesize that shape-based queries will be helpful for finding 3D objects. For instance, shape can combine with function to define classes of objects (e.g. round tables). In this sketch, we report our experiences with shape-based queries based on matching 3D models, 3D sketches, and 2D sketches. The most straight-forward shape-based query interface is to provide the search engine with an existing 3D model and ask it to retrieve similar ones. Our search engine supports this strategy in two ways: the user may upload a 3D model file, or specifiy a 3D model returned in a previous search. However, a suitable 3D model may not be available to the user, in which case one has to be created from scratch. We support this by using Teddy, a simple 3D sketching tool (by T. Igarashi). Unfortunately, we found that even such a simple tool is too difficult to use for the average user. Moreover, only certain types of shapes can be created with Teddy (blobby objects with topological genus zero).