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NPR (Non-photorealistic Rendering). Billy Davidson CS 395 Advanced Graphics January 22, 2004. Non-photorealistic Rendering. Most computer graphics work strives for photorealism Other types of depiction can be more expressive or artistic Depict intrinsic or extrinsic properties?.
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NPR(Non-photorealistic Rendering) Billy Davidson CS 395 Advanced Graphics January 22, 2004
Non-photorealistic Rendering • Most computer graphics work strives for photorealism • Other types of depiction can be more expressive or artistic • Depict intrinsic or extrinsic properties?
Terminology • Image • Picture • Intrinsic/Invariant • Extrinsic • Constancy
Constancy • We do not experience some extrinsic properties of the image we see
3D -> 2D Mappings • Sketches by 7-year old children
Depiction • Depiction is the mapping of properties of the scene to properties of the picture • Traditional 3D -> 2D geometric projection is only one possible meaningful mapping
Projections • Different projections preserve different intrinsic properties
Vision as Inverse Problem • V() = “Visual reaction” function • Not invertible due to ambiguity, emotional factors, etc.
Primary vs. Secondary Space • Respect local rules but not global ones
Primary vs. Secondary Space • Tone mapping
Representation Systems • Spatial system • Primitive system • Attribute system • Mark system
Painterly Rendering • Tarzan
Pen Strokes • Bones
Cel Shading • The Legend of Zelda: The Wind Waker