Sightline (architecture)

Last updated

In architecture, sightlines are a particularly important consideration in the design of civic structures, such as a stage, arena, or monument. They determine the configuration of such items as theater and stadium design, road junction layout and urban planning. In cities such as London, construction within sightlines is restricted to protect the key views of famous landmarks [1]

Contents

Subjects that have a line of sight with one another are said to be intervisible, where intervisibility is the ability of viewers at separate places to see each other without any landform blocking their view.

C-Value

Good sightlines allow spectators to see all areas of a venue stage or field of play. To ensure this designers utilize the C-value, defined as the vertical distance from a spectator's eyes to sightline of the spectator directly behind. The C-value is determined in part by the rake, that is, the upward slope of the seating. [2]

The stadium bowl rake if based on consistent C-values will follow half of a parabola in section. The curvature will be greatest closest to the pitch and will become an increasingly flatter curve as it moves to the upper rows. As a general rule the rake or curve of the seating bowl will flatten as the first row of seats move away from the side-line for a constant C-value. It is impractical to make different step heights for every single row. In practice the riser height is the same for a set of 4 or 5 rows at the bottom of the bowl with the number of rows in each same height set increasing for higher up rows. The uppermost tier could have only 2 or even 1 different step heights.

It is the lowest rows of seats that are the most sensitive to the impact of the C-value because of the very flat view angle to the touch line. The higher seats can have a reduced C-value without impacting as seriously on the clear view of the field of play.

Green Guide Sightline Formula

The existing sightline formula in the Green Guide (Guide to Safety at Sports Grounds) can be traced back to the sightline section of the Guide to Safety at Sports Grounds, also known as Green Guide. It is United Kingdom Government-funded guidance book on spectator safety at sports grounds. On Page 109 Green Guide Fifth Edition, the graphic reference does show the C-Value location.

Sightlines in theatres

Plans of a Movie theater with sightlines Alabama Theatre, 1811 Third Avenue North, Birmingham, Jefferson County, AL HABS ALA,37-BIRM,37- (sheet 4 of 9).png
Plans of a Movie theater with sightlines

Sightline criteria in theaters can include: the "isacoustic curve" [3] [4] [5] defined by John Scott Russell in 1838 and applied at the Auditorium Building in Chicago and the Emery Theatre in Cincinnati; alternate row sightlines where each patron sees between the heads of patrons in the row in front and over the heads of patrons in the second row in front; next row sightlines where each patron sees over the heads of patrons in the row immediately in front; and basic considerations like pointing the chairs more or less toward the performance, being able to see the conductor in the pit, being able to see other patrons, being able to see actors on elevated scenery, and not being obstructed by a wall, railing, column, ceiling overhang, loudspeaker cluster, or any other obstruction. The design of sightlines includes considerations of how much of the stage and scenery each patron can see. For example, can each patron see the top of the scenery or not, and can each patron see the whole stage floor or not? Design of sightlines is divided into two related exercises, vertical sightlines and horizontal sightlines. Design of proper sightlines includes resolving both technical and aesthetic issues. At issue is the emotional response of the audience: whether a performer can hold the audience's attention or not; whether the patron feels they had a "good" seat and their ticket was fairly priced or not; whether the audience gets the emotional impact of the performance or not; and whether the patron wants to come back and see another performance in that theater or not. Building codes restrict the maximum and minimum rise per row, limit the minimum width per row, limit the maximum deviation in the size of steps from row to row to achieve the curvature of the rake, and limit other aspects of sightline design.

Books on theater planning that discuss the design of sightlines. [6] [7] [8]

It is recommended that a spectator's eye height must not be lower than 800 mm above the stage. [9] However, in larger theatres it is acceptable to locate the eye height of the first row on the level of the stage.

Sightlines in stadiums

The spectator view in modern stadia is optimised very carefully to balance the uninterrupted clear view to the field for every seat whilst not making the seating terraces any higher than necessary to satisfy structure, cost and safety considerations.

Typical Architectural Section of a stadium. C-Value section.jpg
Typical Architectural Section of a stadium.

This is done with careful modelling utilizing the C-Value to ensure the ideal rake or curvature of the seating bowl. C-values are improved with a steeper slope or moving the seating rows away from the focus point. Inadequate views result in spectators jumping up for a better view during exciting play. This is an annoyance to others and can lead to fights and in the context of large crowds this can be a serious safety threat. The maximum step height between terraces or rows is usually limited to 540mm. If this is exceeded then a continuous guardrail is required as protection against falling. Even with a 540mm terrace step many spectators become uncomfortable and start to feel the impact of vertigo. An ideal maximum terrace step height that will avoid most people feeling insecure is 450mm.

Sightlines in plan

The C-value is the vertical distance from the spectator eye to where it intersects the sightline of the spectator directly behind. Sightlines C-Value.jpg
The C-value is the vertical distance from the spectator eye to where it intersects the sightline of the spectator directly behind.
The illustration indicates the partially obstructed view of the front row spectators looking at the far corner flag of the adjacent touchline. One eye can see the action on the field whilst vision to the second eye is blocked. Sightline to far end corner flag.JPG
The illustration indicates the partially obstructed view of the front row spectators looking at the far corner flag of the adjacent touchline. One eye can see the action on the field whilst vision to the second eye is blocked.

The C-Value considers the sightlines in the vertical plane. The sightlines in the horizontal plane need to be considered for the front row spectators in the instance where they look acutely sideways, typically adjacent far end corner flag. At the extreme end of the front row, spectators could have their view from one of their eyes blocked by the head of the adjacent spectator. During exciting play this can lead to spectators jumping up out of their seats to get a better view. A clear view for both eyes for all front row spectators can be achieved by the use of curved stands in plan. It can also be argued that with play that is already a long distance away a better view of the game is available on the big video screen.

Focus point

The touch-line (or side-line) and the goal-line are considered the C-Value focus point in stadiums.

Obstructed view seats

There should be a clear view of the playing field from all seats. Roof supports should be eliminated entirely from the seating area. In calculating the sight lines it should be appreciated that advertising boards of 90–100 cm in height may be erected around the field at a distance of five metres from the touch lines and five metres behind the centre of the goal lines. FIFA ticketing carry out an assessment of all seats and those seats that have an obstructed view of the game will be classed obstructed view seats and will not be sold. Quite often these are the first few seats adjacent to the pitch with their view partially blocked by the advertising hoardings. This is an especially big problem with football stadiums that have running tracks around them. These seats are either covered with a fabric and not occupied during the game or the tickets are issued to non-paying spectators.

FIFA C-Value standards

Research

The audience's sightline is an important aspect of the design of viewing venues. For theaters, an algorithm is used to check the sightline from a seat to determine if it is blocked. [10] The development of better methods is the subject of continuing research. In 2011, Yeonhee Kim and Ghang Lee presented an algorithm to derive actual sight area in the early design stage of theater without producing a 3D model. [10] The algorithm uses plan and cross sectional drawings to analyze view of audiences to resolve to address errors of the "sight area rate" algorithm which does not account for sightlines being blocked by the front-row seats in a theater. [10]

Related Research Articles

<span class="mw-page-title-main">Movie theater</span> Venue for viewing films

A movie theater, cinema, or cinema hall, also known as a movie house, picture house, picture theater or simply theater, is a business that contains auditoria for viewing films for public entertainment. Most are commercial operations catering to the general public, who attend by purchasing tickets.

<span class="mw-page-title-main">Aisle</span> Architectural element

An aisle is a linear space for walking with rows of non-walking spaces on both sides. Aisles with seating on both sides can be seen in airplanes, in buildings such as churches, cathedrals, synagogues, meeting halls, parliaments, courtrooms, theatres, and in long passenger vehicles. An aisle floor may be level or, as in theatres, sloping upward from a stage.

<span class="mw-page-title-main">Oregon Shakespeare Festival</span> Repertory theatre in Oregon, United States

The Oregon Shakespeare Festival (OSF) is a regional repertory theatre in Ashland, Oregon, United States, founded in 1935 by Angus L. Bowmer. The Festival now offers matinee and evening performances of a wide range of classic and contemporary plays not limited to Shakespeare. During the Festival, between five and eleven plays are offered in daily rotation six days a week in its three theatres. It welcomed its millionth visitor in 1971, its 10-millionth in 2001, and its 20-millionth visitor in 2015.

<span class="mw-page-title-main">Auditorium</span> A room built to enable an audience to hear and watch performances

An auditorium is a room built to enable an audience to hear and watch performances. For movie theatres, the number of auditoria is expressed as the number of screens. Auditoria can be found in entertainment venues, community halls, and theaters, and may be used for rehearsal, presentation, performing arts productions, or as a learning space.

<span class="mw-page-title-main">Tannadice Park</span> Football stadium in Scotland

Tannadice Park, usually referred to as Tannadice, is a football stadium in Dundee, Scotland. It is the home ground of Dundee United F.C., who have played at Tannadice since the club was founded as Dundee Hibernian in 1909. The stadium has been all-seated since 1994 and has a capacity of 14,223. It is located only 200 yards from Dundee F.C.'s stadium, Dens Park; the two are the closest senior football grounds in the UK.

<span class="mw-page-title-main">Theatre of Dionysus</span> Ancient Greek theatre near the Athens Acropolis, Greece

The Theatre of Dionysus is an ancient Greek theatre in Athens. It is built on the south slope of the Acropolis hill, originally part of the sanctuary of Dionysus Eleuthereus. The first orchestra terrace was constructed on the site around the mid- to late-sixth century BC, where it hosted the City Dionysia. The theatre reached its fullest extent in the fourth century BC under the epistates of Lycurgus when it would have had a capacity of up to 25,000, and was in continuous use down to the Roman period. The theatre then fell into decay in the Byzantine era and was not identified, excavated and restored to its current condition until the nineteenth century.

<span class="mw-page-title-main">Orchestra pit</span>

An orchestra pit is an area in a theater in which musicians perform. The orchestra plays out of general sight in the pit, rather than on the stage as for a concert, when providing music for forms of theatre that require it or when incidental music is required. The conductor typically stands at the front of the orchestra pit facing the stage.

<span class="mw-page-title-main">Stage (theatre)</span> Designated space for the performance of productions

In theatre and performing arts, the stage is a designated space for the performance of productions. The stage serves as a space for actors or performers and a focal point for the audience. As an architectural feature, the stage may consist of a platform or series of platforms. In some cases, these may be temporary or adjustable but in theaters and other buildings devoted to such productions, the stage is often a permanent feature.

<span class="mw-page-title-main">Theater (structure)</span> Performing arts venue (building)

A theater, or playhouse, is a structure where theatrical works, performing arts, and musical concerts are presented. The theater building serves to define the performance and audience spaces. The facility usually is organized to provide support areas for performers, the technical crew and the audience members, as well as the stage where the performance takes place.

<span class="mw-page-title-main">Stadium seating</span> Characteristic seating arrangement

Stadium seating or theater seating is a characteristic seating arrangement that is most commonly associated with performing-arts venues, and derives its name from stadiums, which typically use this arrangement.

<span class="mw-page-title-main">Rake (theatre)</span> Upward slope of a theater stage or audience seating

A rake or raked stage is a theatre stage that slopes upwards, away from the audience. Such a design was typical of English theatre in the Middle Ages and early Modern era, and improves the view and sound for spectators. It also helps with the illusion of perspective: when features of the scenery are made to align with a notional vanishing point beyond the rear of the stage, the rake supports the illusion. These elements of scenery are termed raking pieces.

<span class="mw-page-title-main">Theater drapes and stage curtains</span> Large piece of cloth designed to mask backstage areas of a theater from spectators

Theater drapes and stage curtains are large pieces of cloth that are designed to mask backstage areas of a theater from spectators. They are designed for a variety of specific purposes, moving in different ways and constructed from various fabrics. Many are made from black or other darkly colored, light-absorbing material. Theater drapes represent a portion of any production's soft goods, a category comprising any non-wardrobe, cloth-based element of the stage or scenery. Theater curtains are often pocketed at the bottom to hold weighty chain or to accept pipes to remove their fullness and stretch them tight.

<span class="mw-page-title-main">Grimsby Auditorium</span> Theatre in North East Lincolnshire, England

Grimsby Auditorium is a theatre situated on Cromwell Road, in Grimsby, North East Lincolnshire. With a seated audience capacity of 1,200 the Grimsby Auditorium is the largest professional theatre in Lincolnshire, and one of the larger theatres in the East of England. Built in 1995, it is today managed by Lincs Inspire on behalf of its owners North East Lincolnshire Council.

<span class="mw-page-title-main">Harris Theater (Chicago)</span> Theater in Millennium Park, Chicago, Illinois, United States

The Joan W. and Irving B. Harris Theater for Music and Dance is a 1,499-seat theater for the performing arts located along the northern edge of Millennium Park on Randolph Street in the Loop community area of Chicago in Cook County, Illinois, US. The theater, which is largely underground due to Grant Park-related height restrictions, was named for its primary benefactors, Joan and Irving Harris. It serves as the park's indoor performing venue, a complement to Jay Pritzker Pavilion, which hosts the park's outdoor performances.

There are different types of theatres, but they all have three major parts in common. Theatres are divided into two main sections, the house and the stage; there is also a backstage area in many theatres. The house is the seating area for guests watching a performance and the stage is where the actual performance is given. The backstage area is usually restricted to people who are producing or in the performance.

The American Society of Theatre Consultants (ASTC) is a professional organization whose main goal is to apprise owners, contractors and/or architects of the services that a theatre consultant can perform, whether it be for a new or renovated facility.

<span class="mw-page-title-main">Kalita Humphreys Theater</span>

The Kalita Humphreys Theater is a historic theater in Dallas, Texas (USA). It is the only theater by architect Frank Lloyd Wright and one of the last completed buildings he designed. It was built in 1959 for Dallas Theater Center who still produces original productions on the revolving stage. Other Dallas theater groups also use the Kalita Humphreys Theater throughout the year, including Uptown Players and Second Thought Theater.

<span class="mw-page-title-main">Hyogo Performing Arts Center</span>

The Hyogo Performing Arts Center (HPAC) is a performing arts center in the city of Nishinomiya, Hyōgo Prefecture, Japan, next to Nishinomiya-Kitaguchi Station operated by Hankyu Corporation. The Center was opened in 2005 to mark the ten-year anniversary of the Great Hanshin earthquake which largely devastated Nishinomiya and the surrounding cities.

<span class="mw-page-title-main">Sylvan Theater Historic District</span> Historic district in Iowa, United States

The Sylvan Theater Historic District, also known as Greenwood Park Outdoor Theater, is located in Des Moines, Iowa, United States. It has been listed on the National Register of Historic Places since 1995.

<span class="mw-page-title-main">Mission Ballroom</span> Concert venue in Denver, Colorado

The Mission Ballroom is a concert venue located in the RiNo neighborhood of Denver, Colorado. The building opened in August 2019 with a capacity of nearly 4,000 patrons. Operated by AEG Presents Rocky Mountain, the venue is viewed as a competitor to the Live Nation operated Fillmore Auditorium.

References

  1. "London View Management Framework (LVMF)". London. 2009. Archived from the original on 11 July 2011.
  2. Sheard, Rod (2001). Sports architecture ([New edition] ed.). Spon Press. p. 47. ISBN   9781138982833. OCLC   1017768626.
  3. Russell, John Scott. Treatise on Sightlines. Edinburgh new philosophical Journal 27, 1838.
  4. Journal of the Franklin Institute. Pergamon Press. 1843.
  5. Birkmire, William H. The Planning and Construction of American Theatres. John Wiley & Sons, New York, 1907, p. 90.
  6. Ham, Roderick. Theatres. The Architectural Press, London, Second Edition, 1987, pp. 26–30.
  7. Izenour, George. Theater Design. McGraw-Hill, 1977, pp. 579–599.
  8. Forsythe, Michael. Buildings for Music. The MIT Press, 1985, pp. 235–242.
  9. The Green Guide – Guide to safety at sports ground. Dept of Culture, Media and Sport. 2008. p. 117. ISBN   978-0-11-702074-0. Archived from the original on 27 June 2008.
  10. 1 2 3 Kim, Y. & Lee, G. (2011). "A Study of Sight Area Rate Analysis Algorithm on Theater Design" (PDF). Computing in Civil Engineering: 706–712. doi:10.1061/41182(416)87. ISBN   9780784411827. S2CID   73518339. Archived from the original (PDF) on 19 February 2020.