Entasis is the architectural term for applying a convex curve to a surface for aesthetic purposes, or increasing strength. Its best-known use is in certain orders of Classical columns that diminish in a very gentle curve, rather than in a straight line as they narrow going upward. The human eye would believe that the middle of the column was diminishing in a concave curve half way ups the column, and entasis corrects this.
The word we apply to the design principle is used by the Roman architectural historian Vitruvius, [1] and derives from the Greek word έντείνω (enteino), "to stretch or strain tight". Creating the illusion of greater strength or perception of height may have been an objective in the application of entasis.
Examples of this design principle may be found in cultures throughout the world, from ancient times to contemporary architecture. The first use of entasis is probably in the Later Temple of Aphaia at Aigina, in the 490s BC. [2]
It may be observed among Classical period Greek column designs, for example, in the Doric order temples in Segesta, Selinus, Agrigento, and Paestum.
It was used less frequently in Hellenistic and Roman period architecture.[ citation needed ] The Roman temples built during these periods were sometimes higher than those of the Greeks, with longer and thinner columns.
Chinese carpenters of the Song Dynasty followed designs in the AD 1103 Yingzao Fashi (Treatise on Architectural Methods or State Building Standards) that specified straight columns or those with an entasis on the upper third of the shaft. [3]
Noted architects, such as the Renaissance master Andrea Palladio, also used entasis in the designs of their buildings.
Entasis was often a feature of Inca walls and doorways to counteract the optical illusion that would make the openings appear narrower in their middles. [4]
The opposite effect, applying concave curves in order to narrow surfaces that otherwise would appear to bulge, is also found in architecture, as in the sloping or battered walls of some Tibetan and Bhutanese monasteries and fortresses. The lower parts of such walls, approximately one third, have a slight convex or inward curve, while the higher parts retain an even slope, offsetting the outwardly bulging illusion created by a straight sloping wall. An example in Bhutan is the Dobji Dzong. When some collapsed walls of the Punakha Dzong were rebuilt, around 1996, this asymmetry was not used. [5]
In calligraphy and typography entasis refers to the use of a concave curve to thin — rather than widen — the waist of a stroke [6] or character. In calligraphy this is achieved either through a slight heightening of the pen or brush angle and/or by an increase in the speed of the stroke as it goes into a straight. Visually it is reminiscent of the structure of a bone and a stroke is seen as stronger for it. Entasis in a stroke is intended to counter the illusion a stroke with perfectly straight sides has of bulging slightly.
No record of the rationale for using entasis in columns by Classical builders has yet been discovered.[ citation needed ]. As a result, there has been extensive conjecture over its purpose.
An early view, often articulated and still widespread, espoused by Hero of Alexandria, is that entasis corrects the optical illusion of concavity in the columns that the fallible human eye would create if the correction were not made. [7]
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 smARThistory – Ancient Greek Temples at Paestum, Italy [8] |
Some descriptions of entasis [9] state simply that the technique was an enhancement applied to the more primitive conical columns to make them appear more substantial. Other descriptions argue that the technique emphasizes the substantiality of, not the columns, but rather, of some other part or of the building while being viewed as a whole. Yale architectural historian Vincent Scully argues that entasis emphasizes the weight of the roof of a building by making the building columns appear to bulge under the pressure distributed among them. Danish architect Steen Eiler Rasmussen believed that the effect represented strength by imitating the swelling of a strained muscle, [10] a theory that accords well with the etymology of the word, from the Greek meaning "to strain". [11]
It also has been argued that a "stunted cycloid" column that bulges in the middle is stronger structurally than is a column whose diameter changes according to a linear progression, therefore, having a sound engineering purpose. Because their discussion of the application of the principle has never been discovered, it is unknown, however, whether the early Greeks knew this. [12]
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. The term column applies especially to a large round support with a capital and a base or pedestal, which is made of stone, or appearing to be so. A small wooden or metal support is typically called a post. Supports with a rectangular or other non-round section are usually called piers.
An order in architecture is a certain assemblage of parts subject to uniform established proportions, regulated by the office that each part has to perform. Coming down to the present from Ancient Greek and Ancient Roman civilization, the architectural orders are the styles of classical architecture, each distinguished by its proportions and characteristic profiles and details, and most readily recognizable by the type of column employed. The three orders of architecture—the Doric, Ionic, and Corinthian—originated in Greece. To these the Romans added, in practice if not in name, the Tuscan, which they made simpler than Doric, and the Composite, which was more ornamental than the Corinthian. The architectural order of a classical building is akin to the mode or key of classical music; the grammar or rhetoric of a written composition. It is established by certain modules like the intervals of music, and it raises certain expectations in an audience attuned to its language.
The Corinthian order is the last developed and most ornate of the three principal classical orders of Ancient Greek architecture and Roman architecture. The other two are the Doric order, which was the earliest, followed by the Ionic order. In Ancient Greek architecture, the Corinthian order follows the Ionic in almost all respects, other than the capitals of the columns, though this changed in Roman architecture.
Ancient Greek architecture came from the Greeks, or Hellenics, whose culture flourished on the Greek mainland, the Peloponnese, the Aegean Islands, and in colonies in Anatolia and Italy for a period from about 900 BC until the 1st century AD, with the earliest remaining architectural works dating from around 600 BC.
The Doric order was one of the three orders of ancient Greek and later Roman architecture; the other two canonical orders were the Ionic and the Corinthian. The Doric is most easily recognized by the simple circular capitals at the top of the columns. Originating in the western Doric region of Greece, it is the earliest and, in its essence, the simplest of the orders, though still with complex details in the entablature above.
Pediments are a form of gable in classical architecture, usually of a triangular shape. Pediments are placed above the horizontal structure of the cornice, or entablature if supported by columns. In ancient architecture, a wide and low triangular pediment typically formed the top element of the portico of a Greek temple, a style continued in Roman temples. But large pediments were rare on other types of building before Renaissance architecture. For symmetric designs, it provides a center point and is often used to add grandness to entrances.
Dzong architecture is used for dzongs, a distinctive type of fortified monastery architecture found mainly in Bhutan and Tibet. The architecture is massive in style with towering exterior walls surrounding a complex of courtyards, temples, administrative offices, and monks' accommodation.
Mathematics and architecture are related, since, as with other arts, architects use mathematics for several reasons. Apart from the mathematics needed when engineering buildings, architects use geometry: to define the spatial form of a building; from the Pythagoreans of the sixth century BC onwards, to create forms considered harmonious, and thus to lay out buildings and their surroundings according to mathematical, aesthetic and sometimes religious principles; to decorate buildings with mathematical objects such as tessellations; and to meet environmental goals, such as to minimise wind speeds around the bases of tall buildings.
In architecture the capital or chapiter forms the topmost member of a column. It mediates between the column and the load thrusting down upon it, broadening the area of the column's supporting surface. The capital, projecting on each side as it rises to support the abacus, joins the usually square abacus and the usually circular shaft of the column. The capital may be convex, as in the Doric order; concave, as in the inverted bell of the Corinthian order; or scrolling out, as in the Ionic order. These form the three principal types on which all capitals in the classical tradition are based. The Composite order established in the 16th century on a hint from the Arch of Titus, adds Ionic volutes to Corinthian acanthus leaves.
A portico is a porch leading to the entrance of a building, or extended as a colonnade, with a roof structure over a walkway, supported by columns or enclosed by walls. This idea was widely used in ancient Greece and has influenced many cultures, including most Western cultures.
Greek temples were structures built to house deity statues within Greek sanctuaries in ancient Greek religion. The temple interiors did not serve as meeting places, since the sacrifices and rituals dedicated to the respective ouranic deity took place outside them, within the wider precinct of the sanctuary, which might be large. Temples were frequently used to store votive offerings. They are the most important and most widespread surviving building type in Greek architecture. In the Hellenistic kingdoms of Southwest Asia and of North Africa, buildings erected to fulfill the functions of a temple often continued to follow the local traditions. Even where a Greek influence is visible, such structures are not normally considered as Greek temples. This applies, for example, to the Graeco-Parthian and Bactrian temples, or to the Ptolemaic examples, which follow Egyptian tradition. Most Greek temples were oriented astronomically.
A cella or naos is the inner chamber of an ancient Greek or Roman temple in classical antiquity. Its enclosure within walls has given rise to extended meanings, of a hermit's or monk's cell, and since the 17th century, of a biological cell in plants or animals.
Paestum was a major ancient Greek city on the coast of the Tyrrhenian Sea, in Magna Graecia. The ruins of Paestum are famous for their three ancient Greek temples in the Doric order dating from about 550 to 450 BC that are in an excellent state of preservation. The city walls and amphitheatre are largely intact, and the bottom of the walls of many other structures remain, as well as paved roads. The site is open to the public, and there is a modern national museum within it, which also contains the finds from the associated Greek site of Foce del Sele.
Moulding, or molding, also coving, is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster, but may be of plastic or reformed wood. In classical architecture and sculpture, the moulding is often carved in marble or other stones. In historic architecture, and some expensive modern buildings, it may be formed in place with plaster.
Triglyph is an architectural term for the vertically channeled tablets of the Doric frieze in classical architecture, so called because of the angular channels in them. The rectangular recessed spaces between the triglyphs on a Doric frieze are called metopes. The raised spaces between the channels themselves are called femur in Latin or meros in Greek. In the strict tradition of classical architecture, a set of guttae, the six triangular "pegs" below, always go with a triglyph above, and the pair of features are only found in entablatures of buildings using the Doric order. The absence of the pair effectively converts a building from being in the Doric order to being in the Tuscan order.
This page is a glossary of architecture.
A cavetto is a concave moulding with a regular curved profile that is part of a circle, widely used in architecture as well as furniture, picture frames, metalwork and other decorative arts. In describing vessels and similar shapes in pottery, metalwork and related fields, "cavetto" may be used of a variety of concave curves running round objects. The word comes from Italian, as a diminutive of cave, from the Latin for "hollow". A vernacular alternative is "cove", most often used where interior walls curve at the top to make a transition to the roof, or for "upside down" cavettos at the bases of elements.
Fluting in architecture and the decorative arts consists of shallow grooves running along a surface. The term typically refers to the curved grooves (flutes) running vertically on a column shaft or a pilaster, but is not restricted to those two applications. If the hollowing out of material meets in a point, the point is called an arris. If the raised ridge between two flutes appears flat, the ridge is a fillet.
The Temple of Hera II, is a Greek temple of Magna Graecia in Paestum, Campania, Italy. It was built in the Doric order around 460–450 BC, just north of the first Hera Temple of around 550–525 BC. If still in use by the 4th-and 5th century, it would have been closed during the persecution of pagans in the late Roman Empire.
Etruscan architecture was created between about 900 BC and 27 BC, when the expanding civilization of ancient Rome finally absorbed Etruscan civilization. The Etruscans were considerable builders in stone, wood and other materials of temples, houses, tombs and city walls, as well as bridges and roads. The only structures remaining in quantity in anything like their original condition are tombs and walls, but through archaeology and other sources we have a good deal of information on what once existed.