Nadir camera rigging that utilizes more than 2 lenses to capture 360º footage, the nadir location follows the same logic as the astronomical definition in that it is located opposite of the zenith, or in the same direction as the gravitational pull in relation to the camera rigging. Nadir The nadir (, ; from / ALA-LC: "naẓīr", meaning "counterpart") is the direction pointing directly "below" a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface there. Since the concept of "being below" is itself somewhat vague, scientists define the
Overhead valve engine the first V-8 engine with OHV's to be produced on a wide scale. General Motors is the world's largest pushrod engine producer, producing I4, V6 and V8 pushrod engines. Most other companies use overhead cams. Nowadays, automotive use of side-valves has virtually disappeared, and valves are almost all "overhead". However, most are now driven more directly by the overhead camshaft system. Few pushrod-type engines remain in production outside of the United States market. This is in part a result of some countries passing laws to tax engines based on displacement, because displacement is somewhat related to the emissions and fuel