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Precomputed Global Illumination of Isosurfaces. Master’s Defense Kevin Beason David C. Banks, Advisor. Computer Graphics. Sphere { position 1 0 0 }. Visualization. Image. Data. Scalar Field. Level Sets. Example Level Sets. Rendering. Photon Mapping. Thesis Statement.
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Precomputed Global Illumination of Isosurfaces Master’s Defense Kevin BeasonDavid C. Banks, Advisor
Computer Graphics Sphere { position 1 0 0 }
Visualization Image Data
Rendering Photon Mapping
Thesis Statement • Level sets can be displayed in real time with high quality graphics
Is this new? Local Illumination Global Illumination Fast (hw) X NEW Slow(sw) X X
Local vs. Global Illumination Local Global
Rendering Equation Global Local
Image Credits • Neuron - Blanco, Ouimet, Banks, Beason • Vislab - Yagi, Banks, Beason • Boatwake - Sussman, Banks, Beason • Atrium - Dabrovic, Beason
Global Illumination of Isosurfaces • Global Illumination is good • How do I apply it to isosurfaces quickly? • Precompute GI for all level sets Lc • Save solutions
How? • Naïve approach: • Extract a level set • Illuminate it (wait…) • Save illumination • Repeat for every isovalue c • Retrieve at runtime amira
Level sets • Lc = (x,y) : h(x,y) = c
Raised Level Sets = (x, y, h(x,y)) : h(x,y) = c
Physical Example 2D Analytic Heightfield Function plaster
Mathematical Model • Flattened Light Transport • 2D case
Duality • Two isosurfaces • Same light
Flat 3D Rend. Eqn. • Requires modification of Emission and Reflection
Flat 4D Rend Eqn. • Behaves just like ordinary 3D light • Operates it in raised leaf of R4
Sample Illumination on Graph Samples are taken uniformly in Domain (R3)
Interpolate into 3D Texture • Use Shepard Interpolation • Or Tent Filter
Apply Texture • Use Marching Squares to extract Level Set • Use texture-mapping to apply 3D texture =
Results • Movies • Amira
Thank You • Brad Futch, Josh Grant, Wilfredo Blanco (amira network), Hui Song • Dr. Ouimet, Dr. Hussaini, Dr. Piekarewicz, Dr. Smith (Datasets) • Dr. Liu, Dr. Sussman (Committee) • Dr. Banks (Advisor)