Siggraph2019 Geometric Algebra

Caption notes

At SIGGRAPH 2019, Charles Gunn and Steven De Keninck ask how a graphics program’s choice of representation shapes the operations that follow. They introduce Euclidean projective geometric algebra as a common algebra for points, lines, and planes. In the plane, two distinct parallel lines meet at an ideal point that represents their shared direction, letting the projective model express both parallel and intersecting cases. They also discuss two motions together. Reflecting successively across intersecting lines produces a rotation, while reflecting successively across distinct parallel lines produces a translation.