Solid angle a solid angle in steradians is the following ratio: where A is the spherical surface area and r is the radius of the considered sphere. Solid angles are often used in physics, in particular astrophysics. The solid angle of an object that is very far away is roughly proportional to the ratio of area to squared distance. Here "area" means the area of the object when projected along the viewing direction. The solid angle of a sphere measured from any point in its interior is 4 sr, and the solid angle subtended at the center of a cube by one
Solid surface such as metal alloys or polymers. Solid surfaces are synthetic surfaces manufactured from polymeric materials. Tools of surface fabrication include routers, drills, templates, clamps, ovens, suction cup grips, and table saws. Larger surface fabricators may also use CNC routers. For all but the simplest jobs, surface fabrication usually takes place in the workshop, after which the finished product is assembled and installed at the work site. Installation of multi-part surfaces, such as "L" and "U" shaped countertops, often involves complex work with specialized tools, to create a seamless result. Solid surfaces is used in the following environment : Solid surface