Computer Aided Design
Computer-aided design (CAD) is the use of computers (or workstations) to aid in the creation, modification, analysis, or optimization of a design.[1] This software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing.[2] Designs made through CAD software are helpful in protecting products and inventions when used in patent applications. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The terms computer-aided drafting (CAD) and computer aided design and drafting (CADD) is also used.[3]
Its use in designing electronic systems is known as electronic design automation (EDA). In mechanical design it is known as mechanical design automation (MDA), which includes the process of creating a technical drawing with the use of computer software.[4]
CAD software for mechanical design uses either vector-based graphics to depict the objects of traditional drafting, or may also produce raster graphics showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual drafting of technical and engineering drawings, the output of CAD must convey information, such as materials, processes, dimensions, and tolerances, according to application-specific conventions.
CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) space.[5][6]: 71, 106
CAD is an important industrial art extensively used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prosthetics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising and technical manuals, often called DCC digital content creation. The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of the 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics (both hardware and software), and discrete differential geometry.[7]
The design of geometric models for object shapes, in particular, is occasionally called computer-aided geometric design (CAGD).[8]
Ely (/ˈiːli/ (About this soundlisten) EE-lee) is a cathedral city in Cambridgeshire, England, about 14 miles (23 km) north-northeast of Cambridge and about 80 miles (129 km) by road from London. Æthelthryth (also known as Etheldreda) founded an abbey at Ely in 673; the abbey was destroyed in 870 by Danish invaders and was rebuilt by Æthelwold, Bishop of Winchester, in 970. Construction of the cathedral was started in 1083 by a Norman abbot, Simeon. Alan of Walsingham's octagon, built over Ely's nave crossing between 1322 and 1328, is the "greatest individual achievement of architectural genius at Ely Cathedral", according to architectural historian Nikolaus Pevsner. Building continued until the dissolution of the abbey in 1539 during the Reformation. The cathedral was sympathetically restored between 1845 and 1870 by the architect George Gilbert Scott. As the seat of a diocese, Ely has long been considered a city; in 1974, city status was granted by royal charter.
Ely is built on a 23-square-mile (60 km2) Kimmeridge Clay island which, at 85 feet (26 m), is the highest land in the Fens. Major rivers including the Witham, Welland, Nene and Great Ouse feed into the Fens and, until draining commenced in the 17th century, formed freshwater marshes and meres within which peat was laid down. There are two Sites of Special Scientific Interest in the city: a former Kimmeridge Clay quarry, and one of the United Kingdom's best remaining examples of medieval ridge and furrow agriculture.
The economy of the region is mainly agricultural. Before the Fens were drained, the harvesting of osier (willow) and sedge (rush) and the extraction of peat were important activities, as were eel fishing—from which the settlement's name may have been derived—and wildfowling. The city had been the centre of local pottery production for more than 700 years, including pottery known as Babylon ware. A Roman road, Akeman Street, passes through the city; the southern end is at Ermine Street near Wimpole and its northern end is at Brancaster. Little direct evidence of Roman occupation in Ely exists, although there are nearby Roman settlements such as those at Little Thetford and Stretham. A coach route, known to have existed in 1753 between Ely and Cambridge, was improved in 1769 as a turnpike (toll road). The present-day A10 closely follows this route; a southwestern bypass of the city was built in 1986. Ely railway station, built in 1845, is on the Fen Line and is now a railway hub, with lines north to King's Lynn, northwest to Peterborough, east to Norwich, southeast to Ipswich and south to Cambridge and London.
The King's School is a coeducational boarding school which was granted a royal charter in 1541 by Henry VIII; the school claims to have existed since 970. Henry I granted the first annual Fair, Saint Audrey's (or Etheldreda's) seven-day event, to the abbot and convent on 10 October 1189; the word "tawdry" originates from cheap lace sold at this fair. Present-day annual events include the Eel Festival in May, established in 2004, and a fireworks display in Ely Park, first staged in 1974. The city of Ely has been twinned with Denmark's oldest town, Ribe, since 1956. Ely City Football Club was formed in 1885.