Solid angle to the unit sphere with center P, which can be calculated as the surface integral: where formula_5 is the unit vector corresponding to formula_6, the position vector of an infinitesimal area of surface with respect to point P, and where formula_7 represents the unit normal vector to . Even if the projection on the unit sphere to the surface S is not isomorphic, the multiple folds are correctly considered according to the surface orientation described by the sign of the scalar product formula_8. Thus one can approximate the solid angle subtended by a small facet having flat surface area ,
Solid surface then injected into the cavity of the mould. Many finishes are available including, gel coated, matte, gloss, metallic and textured. A "surface fabricator" shapes and installs functional and decorative surfaces, usually in buildings. Surface fabrication, as a distinct professional enterprise, usually involves complex tasks of surface shaping. A leading case is countertop fabrication. For interior spaces, surfaces include solid coverings or decking for floors or walls, and countertops for kitchens, bathrooms, and workspaces. Natural surfaces are composed of naturally occurring materials like wood, stone, mineral, clay, gum and resin. Synthetic surfaces contain, in addition to any natural materials, man-made substances