1. In a graphics system for processing geometric objects, said graphics system including a spatial hierarchy having a plurality of levels ranging from a finest level to a coarsest level, said spatial hierarchy being organized as a plurality of nested tiles that progress in scale by powers of two, each of said tiles defining a coordinate frame, said tiles including a first tile and a second tile, the second tile being nested inside the first tile, a method for evaluating a polynomial equation having coefficients and describing a geometric object, said method comprising: computing said coefficients of said polynomial equation relative to said coordinate frame of said first tile; and transforming said polynomial equation to said coordinate frame of said second tile.