Precomputed Global Illumination of Isosurfaces Master’s Defense Kevin Beason David C. Banks, Advisor

Computer Graphics Sphere { position }

Visualization Data Image

Scalar Field

Level Sets

Example Level Sets

Rendering Photon Mapping

Thesis Statement Level sets can be displayed in real time with high quality graphics

Is this new? Local IlluminationGlobal Illumination Fast (hw) Slow(sw) X XX NEW

Local vs. Global Illumination Local Global

Rendering Equation Global Local

Perceptual Cues

Boat wake

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 L c Save solutions

How? Naïve approach: Extract a level set Illuminate it (wait…) Save illumination Repeat for every isovalue c Retrieve at runtime amira

Example heightfield

Scalar Field

Level sets L c = (x,y) : h(x,y) = c

Raised Level Sets = (x, y, h(x,y)) : h(x,y) = c

Flat Light in D

Flat Light in DxR

Flat Light on Graph

Physical Example 2D Analytic Heightfield Function plaster

Flattened Light

Raising water level

Sum of Level Sets Illumination

Mathematical Model Flattened Light Transport 2D case

Duality Two isosurfaces Same light

Ordinary Light

Flattened 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 R 4

Ordinary vs. Flattened

Sample Illumination on Graph Samples are taken uniformly in Domain (R 3 )

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)