When implicit surface is defined by equation f(x,y,z)=0, the object defined by the implicit function is the set of points which satisfy the inequation f(x,y,z)≥0. For the object, it's possible to do union, intersection and subtraction etc using R-function. As a special implicit function, the Metaball function can also be used in blend and deformation for solid modeling except the common properties of implicit function. It is proved that R-function can be used in Boolean operation of solid modeling and Metaball model can be used in the blending of shape.