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,要得到所構(gòu)建物體的外表面,也就是相關(guān)隱函數(shù)的零集合,需要對隱函數(shù)進(jìn)行顯示求解或使用一些面片生成算法如marching cubes算法。