Michael Burns will present his preFPO on Friday April 11 at 10:30AM in Room 402. The members of his committee are: Adam Finkelstein, advisor; Szymon Rusinkiewicz and Doug DeCarlo (Rutgers), readers; Perry Cook and Tom Funkhouser, nonreaders. Everyone is invited to attend his talk. His abstract follows below. -------------------------- Title: Efficient and Comprehensible Visualization of Complex 3D Data As computing power increases, so does our power to scan or model increasingly complex 3D objects and scenes. Complexity may arise by the structure of the scene, such as having many nested objects, or by a large quantity of data. Traditional rendering pipelines fall short in exposing occluded objects or surfaces of interest in such complex scenes, and may result in important objects being visualized ineffectively or not at all. This thesis presents several techniques for creating comprehensible renderings of these complex scenes. Line drawings can be used to effectively visualize large scenes of volumetric data. Such data sets, which may result from fluid simulations or medical scans, often contain nested features of interest, such as bones being inside flesh in a CT scan. By using lines derived from implicitly defined isosurfaces, we can visualize several nested structures at once. Furthermore, by using lines instead of traditional volumetric rendering or isosurface extraction, we can generate images by processing far fewer data points for large, high- resolution volumetric data sets. For more traditional surfaces renderings, interior objects can be exposed by using cutaway structures. These view-dependent cutaways are defined by a cutaway surface that can be computed and represented either geometrically or by a screen-aligned height field. In either case, one can use this cutaway surface to affect both volumetric and polygonal renderings. We show how contextual cutaways can be used in volumetric renderings to expose interior materials of interest along with a specially defined region of interest, and present an example of rendering live Ultrasound data in the context of a medical CT scan, with various tissues being exposed around the plane of the Ultrasound probe. We also show how cutaways can be used in polygonal renderings to expose objects of interest in complex scenes, presenting examples in architectural modeling where furniture and interior structures can be viewed in the context of the exterior of the building.