•2D. Line is set
of points (x,y) for which (a,b,c).(x,y,1)T=0. Suppose we
rotate points by R. Notice that:
•(a,b,c)RT R(x,y,1)T
•
•So, (a,b,c)RT is the rotation
of the line (a,b,c).
•Surface normals are similar, except they are defined by (a,b,c).(x,y,z)T = 0