VideoTrace is an application that lets you easily create 3D models from things in video clips. The user interacts with VideoTrace by tracing the shape of the object to be modeled over one or more frames of the video. By interpreting the sketch drawn by the user in light of 3D information obtained from computer vision techniques, a small number of simple 2D interactions
can be used to generate a realistic 3D model.

http://www.virtualworldlets.net/Worlds/Listings/CGILibraries/VideoTrace1.jpg

Each of the sketching operations in VideoTrace provides an intuitive
and powerful means of modelling shape from video, and executes quickly
enough to be used interactively. Immediate feedback allows the user to
model rapidly those parts of the scene which are of interest and to the
level of detail required. The combination of automated and manual
reconstruction allows VideoTrace to model parts of the scene not
visible, and to succeed in cases where purely automated approaches
would fail.

The University of Adelaide’s Australian Centre for Visual Technologies is developing VideTrace.

There are a number of applications of the VideoTrace technology,
including modelling parts of the real world for insertion into virtual
worlds. You may want to model your house, in order to put it into
Google Earth, or your couch, in order to take it with you into Second
Life, for example.

Video at The Australian Centre for Visual Technologies