1. 3-D Data cs5984: Information Visualization Chris North

2. Review Visualizing document collections:

3. Where are we? Multi-D 1D 2D Hierarchies/Trees Networks/Graphs Document collections 3D Design Principles Empirical Evaluation Java Development Visual Overviews Multiple Views Peripheral Views

4. 3-D Data Surface data Volume data

5. Surface Data Vector/Polygonal surface data Polygons approximate surfaces of 3D objects Paint textures on surfaces Examples: Quake

6. VRML Protein example http://www.rcsb.org/pdb/cgi/explore.cgi?job=graphics&pdbId=4TNA&page=&pid=16250983503380

7. Navigation Move camera Move objects 6 degrees of freedom: 3 translation 3 rotation Zoom = translate forward? y z x x y z

8. Zoom

9. Graphics Projection Z-buffer Shading, texture mapping, … Ray Tracing Shoot rays from camera into scene Reflection, …

10. Challenges Navigation Occlusion, See inside?

11. Volume Data Voxel volume data Fully sampled contents of 3D objects Voxel = 3D pixel; point in a 3D image Volume = 3D array Examples: MRI, CaT scan: »Measures tissue density at each point in space Visible Human »slice and photograph 2-D: 3-D:

12. Slicing Visible Human Explorer (north et al) http://www.cs.umd.edu/hcil/visible-human/vhp.mpg

13. Slice and Dice

14. 3D Cutting Plane Ken Hinckley, UVA

15. Surface Reconstruction Generate surface data from volume data Iso-surfaces Marching Cubes algorithm Look at cubes of 8 voxels Cube is on surface if: ??? Generate polygons Smooth

16. Volume Rendering Ray Casting Like x-ray Accumulate color & opacity along rays “Transfer functions” Splatting Like projection Reverse of ray-casting Calculate each voxel’s contribution to image

17. Transparency: X-Ray Vision SurfaceVolume http://www.uke.uni-hamburg.de/institute/imdm/idv/vm3dn/io_xray_combined.en.html http://graphics.stanford.edu/software/volpack/movies/vp_movies.html

18. Combining it all together Voxel-Man Hamburg University http://www.uke.uni-hamburg.de/institute/imdm/idv/vm3dn/io_thorax.en.html

19. Interactive Volume Rendering Kniss, “Interactive volume rendering with direct manipulation” Xueqi, Mahesh

20. 3-D volume data: Digital Video 3D: Stack 2D video frames time x y

21. Slicing Digital Video Red’s Nightmare video in VHE http://vtopus.cs.vt.edu/~north/infoviz/RedsNightmare.mpg Full overview: time zoom Scene change still credits motion Pan left

22. Assignment Thurs: Workspaces Robertson, “Task Gallery” » supriya, varun Upson, “AVS” » christa, jun Dec 7: ACM CHI short papers due Dec 18: Project Final Paper due March: IEEE InfoVis papers due

23. Future Thanksgiving break Tues 27: Debates, 2D vs 3D Kobsa, “Empirical comparison of comm infovis systems” » kunal, zhiping Thurs 29: How (not) to lie with visualization Other fun stuff?

24. Project Presentations Dec 4: Dec 6: Dec 11:

25. Upcoming Opportunities Independent studies Thesis projects GTAs GRAs