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CS 4300 Computer Graphics. Prof. Harriet Fell Fall 2012 Lecture 12 – October 1, 2012. Linear Transformations. ala “Foundations of 3D Computer Graphics” by Steven J. Gortler a point in the real world represented by a coordinate vector
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CS 4300Computer Graphics Prof. Harriet Fell Fall 2012 Lecture 12 – October 1, 2012
Linear Transformations • ala “Foundations of 3D Computer Graphics” by Steven J. Gortler • a point in the real world represented by a coordinate vector • x, y, zare numbers that give the position of the point w.r.t an agreed upon coordinate system • with an agreed upon origin • agreed upon directions
Concepts and Notation • point • vector • coordinate vector c • numerical object with real numbers • bold for vertical collection • coordinate system • bold for vertical collection • t makes it horizontal collection • for collection of vectors
Vectors, Coordinate Vectors, Bases • vectoris abstract geometric entity that represents motion between two point in the world • coordinate vector is a set of numbers used to specify a vector in an agreed upon coordinate system. • vector space V is set of vectors that satisfies certain rules – (think actual motions between actual geometric points) • basis is a small set of vectors that can be used to (uniquely) produce the entire set of vectors using vector + and scalar multiplication.
Linear Transformations by 3x3 Matrices • Linear Transformation
Points and Frames • point – fixed place in a geometric world • vector – motion between two points • addition and scalar multiplication make sense for vectors but not for points • other operations that make sense • apply a linear transformation to a point • translate a point