An implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives implicit representations using r - function theory . the surface corresponding to the zero - set of the implicit equation is efficiently and directly polygonized using the primitives parametric forms 但是，要得到所构建物体的外表面，也就是相关隐函数的零集合，需要对隐函数进行显示求解或使用一些面片生成算法如marching cubes算法。
