What s Missing? Brian Budge 5/31/04

Transcription

1 What s Missing? Brian Budge budge@cs.ucdavis.edu 5/31/04 Institute for Data Analysis and Visualization : University of California, Davis

2 What s wrong with these images? Slide 2 of 20

3 What can we do? More complex geometry If you have non-polygonal surfaces, you shouldn t see polygons Backgrounds are important this is because... The smallest details count! Anything that can be noticed by the human eye, will also be missed More complex physical simulation Again, humans are reasonably good at recognizing complexity (which isn t to say that it necessarily needs to be correct) Lots of effects are noticeable. While they won t necessarily be missed, they add richness that can be convincing Imperfections!!! When was the last time you walked around and found shiny chrome everything? Floors without shoe marks? Metals without scratches? Slide 3 of 20

4 Yeah, texture is great, but... Texture can add a lot of complexity, replacement for geometry in most cases but it s not a reasonable Excellent for labels, wrappers, things that are printed - 2D mappings We need real geometry, especially if the viewer is relatively close Even bump mapping isn t the cure-all. It will look reasonable from an orthogonal viewpoint, and completely wrong from incident angles. Even from orthogonal, though, it will make lighting simulations incorrect. Important research to transition from geometry to bump mapping to BRDF Slide 4 of 20

5 Geometry Many ways to increase geometric complexity Triangle meshes Displacement maps [32] Height Fields [15] Hypertextures (isosurfaces) [28] Slide 5 of 20

6 Take more physics into account We already have reflection and refraction, what more could we want? More realistic BRDFs [19, 1, 23, 2] We ve discussed a lot of these Ideally we could use measured data Polarization [35] Could be very important for manufacturers of sunglasses! Slide 6 of 20

7 Spectral rendering [5] We ve seen this is important even for our non-wavelength dependent interactions even more important when you have wavelenght dependent effects Thin film interference [12] Subsurface scattering and participating media [13, 18] Flourescence and phosphorescence [11] Slide 7 of 20

8 Dispersion [34] Wave optics effects like diffraction [33] Slide 8 of 20

9 Special cases - infinitely many! Humans hair, skin, eyes [22, 14, 21] Plants structures, subsurface scattering models [4, 10] Water structure, impurities [9, 30] Slide 9 of 20

10 Terrain [26, 20] Atmosphere [29, 16] More! Slide 10 of 20

11 Imperfections Dust rendering and modeling of dust accumulation [3, 31] Metallic patinas [7] Corrosion [24] Scratches [25] Wet materials spills etc... [17] Simulation of impacts on surfaces [27] Weathering [6, 8] Much more! Slide 11 of 20

12 The End In conclusion - we need to add complexity to achieve realism It doesn t always have to be right as long as you can fool the human eye Or, it can be right for special cases - as long as those are the cases you re rendering Slide 12 of 20

13 [1] ASHIKHMIN, M., AND SHIRLEY, P. S. An anisotropic phong brdf model. Slide 13 of 20

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