Basic solids(block, elipsoid, cylinder, torus) and many other shapes are described with unified equations (3 and 4). All required primitives can be obtained only by varying superquadric parameters. In fact when selecting superquadric as primitive for CSG only one algorithm for calculating shape intersections is required. This simplification in CSG kernel provides robustness to any type of object representation. Mass properties with superquadrics are easily calculated. Normals for shading with polygon representations are derived from basic equations.