IASLonline NetArt: Theory

Thomas Dreher

History of Computer Art

V. Reactive Installations and Virtual Reality
V.1 Operations of Observers on the Interface to the Image Simulation

in German


V.1 Operations of Observers on the Interface to the Image Simulation

Between the seventies and nineties Myron Krueger, Jeffrey Shaw and Peter Weibel realised reactive installations. The installations presented below react to observer operations 1: A technical system using cameras or especially designed surfaces as sensors can be provoked by observers with body movements to react with an output. The computer-aided systems change their projections of two-(Krueger) and three-dimensional (Shaw, Weibel) picture worlds in reacting to the input being produced by observers and registered by sensors. If observers act on or before an interface with the goal to change the projections then they provoke questions about the self-orientation mediating between spaces of the projected images and the real space.

With their operations on an interface in the real space the observers cause changes in a not walkable virtual space. The navigation in an animated `space of the image´ (Bildraum) with gravitationless objects is coordinated by observers on an interface under gravity conditions. Observers coordinate their actions on the technical interface with the `spaces of the images´ in recursions: The system´s possibilities can be reconstructed in cognitive reactions (observing operations) to the triggered mechanical reactions. For further explorations of these possibilities observers modify their actions on the interface (observer operations). These exploring observer operations cause modifications in the cognitive efforts to reconstruct the system´s possibilities (observing operations). The question if the system can be reconstructed adequately with the last reconceptualisation may lead to further observer operations.

Observers can construct a mental plan for the technical functions in a highly simplified form if it seems to be useful for explorations of the virtual space presenting the projected animated image on an interface. Recursions between observing operations (Beobachtungsoperationen) and observer operations (Beobachteroperationen) are parts of the investigations exploring the presented programmed animations. Observers can construct a second plan containing the relations between the technical interface and cognitive recursions to navigate their explorative behavior.

The artists and programmers did not publish the codes for the technical functions of the installations explained below. The effects of these functions can be tested by observers in operating on or before the installations´ technical interfaces and looking on the projections or on screen presentations of the animations.

Myron Krueger: Psychic Space 1971

Krueger: Myron: Psychic Space, 1971, ground plan
(Krueger: Reality 1991, p.26, fig.2.9).

In 1971 Myron Krueger´s "Psychic Space" was installed in the Memorial Union Gallery of the University of Wisconsin. From the exhibition space an installation space was separated by partition walls. This space contained 48 black pressure-sensitive base plates and a projection surface. The longitudinal walls are made of black polyethylene. Observers were able to move on the base plates between the rear projection on one narrow side and the other narrow side being coated with phosphorescent paint. In moving on the plates observers activated a sound program and an animation program. A minicomputer PDP-11 since 1969) of the Digital Equipment Corporation (DEC) transmitted the input of the pressure-sensitive base plates to a Moog Synthesizer (since 1964) generating sounds. An Adage AGT-10 Graphic Display Computer supplied the rear-projection with the ground plan of a labyrinth. Within the labyrinth observers could move a rhombus by changing their locations on the base plates – not without activating the sound generation.

The sound generation reacted to observers entering and leaving the "sensing grid" as well as to actions like jumping on the base plates and lifting legs. The latter two operations of observers suspended the sound generation. After a `playtime´ used for explorations of the base plates observers could activate high- and low-pitched sounds on different sides and recognised this interface functioning like a keyboard of a musical instrument. But the distribution of pitch levels on the "sensory grid" could rotate 90 degrees. This could cause irritations.

The Adage graphics system´s monitor was recorded by a camera and the rear projection presented its images in the environment. When observers entered the enviroment then they saw the rear projection of a square. Via pressures on the base plates observers could move the rhombus to the square. With the approximation of the rhombus and the square the projection of the labyrinth started. The projection of this configuration was dissolved if observers didn´t move the rhombus within the limits of the labyrinth. The observers could easier be successful in directing the rhombus to the goal because the projected obstacles contained target-oriented barriers. But the labyrinth was dissolved before observers could reach its innermost part. 2

Krueger, Myron: Videoplace, since 1974, film, studio in the Museum of Natural History, Vernon/Connecticut 1988.

Krueger developed "Videoplace" from 1974 to the nineties. 3 "Videoplace" takes up the closed-circuit video installation prefigured in 1969 in Nam June Paik´s "Participation TV II" 4 and modifies it: In Paik´s installation observers could use a control panel to manipulate video images recorded by video cameras and projected on monitors. Krueger replaces Paik´s interface (control panel and cameras) by a series of programmes transforming the recordings of a black/white-surveillance camera. The camera mounted underneath the projection surface records observers and their operations "against a brightly backlit sheet of translucent plastic". On a computer with parallel active "specialized processors" the software gathers the camera´s input as a "binary image" transforming the observers´ contours in a field with ones and zeros for recognised/non recognised observer operations. The software registers motions of heads, hands, fingers, legs and feet. 5 These data are used by programmes trnsforming and colouring the observers´ contours in different manners. If obervers leave the camera´s range of vision then the system switches to another animation programme. 6 "Videoplace´s" switching system and programmes replace Paik´s control panel and the functions of the video synthesizer.

Krueger, Myron: Videoplace, since 1974, presentation of programmes in 1985.

The programme "Individual Medley" (since 1976 in b/w, since 1979/80 in colour) was developed for "Videoplace" and uses overlaps of eight contours recorded successively ("sampling-rate") and stored them for the animation programmes´ different kinds of colourising and sound generations. Observers have to move, if they want to activate the programmes for animations and to keep them running:

...a participant creates feedback for himself only as long as he keeps moving. 7

"Critter" offers observers to act with their contours with and against a sign figure constituted by a circle – as its head – with two little circles as eyes and four lines as legs: A dialogue develops between the machine creature and the observer – on the part of the observer based on the body language, without control panel or manual. 8 "Individual Medley" and "Critter" are only two of fourteen examples presented in 1991 by Krueger in his book "Artificial Reality II". 9

In 1975 Krueger installed "Videoplace" for the first time in the Milwaukee Art Museum: Two installations with camera-computer-projector units were located in two rooms in 300 feet distance. In each room the contours of the persons were projected who acted before the cameras of both installations. Observers looked at their own contours and at the contours of observers of the other installation: Observers in both rooms communicated with each other via the projections. 10

Krueger, Myron: Videoplace, since 1974, with videodesk, 1987.
Presentation of programmes.

In 1987 Krueger realised "Videodesk" for an "operator" being familiar with the "Videoplace" system. If "Videodesk" is combined with "Videoplace" then the operator is enabled to provoke the observers in "Videoplace" to interactions in various ways.

The "Videodesk" operator sits on a table. On a monitor behind the table he sees the contours of his hands recorded by a camera hanging from above the table. This input is transmitted to the "Videoplace" system. Some programmes are developed for the interactions between the observers´ contours in "Videoplace" and the recordings of the operator´s hands in "Videodesk".

In "Man-Ipulate" the observer´s silhouette falls over after being tossed on its upper body by the operator´s hand, meanwhile in "Telecision" observers can divide the contour of the operator´s arm as if they can separate his hand from his body. 11 In "Artwheels" observers move their contours between the operator´s hands. 12

Since 1983 Jeffrey Shaw develops reactive installations with image projections. 13 The observers´ coordinations between the orientations in real spaces and spaces of images are provoked in "Legible City" (variants for Manhattan, Amsterdam and Karlsruhe, 1989-91) and in "The Virtual Museum" (1991) to be organized in multi-layered ways: Observers are prompted to activate and control mutations of the space of the image by body motions (observer operations) on the interface. Navigating in the virtual space with its three-dimensional `gravitationless´ elements is made possible in realising body motions under the conditions of gravity.

Shaw, Jeffrey: The Legible City, reactive installation, 1989-91.

In "Legible City" the houses of a city´s simulation are replaced by letters. (In the variants for Amsterdam and Karlsruhe) the letters possess the height of the replaced houses and are parts of a text describing the urban situations reconstructed by the simulation. Before the projection wall a bicycle is mounted on the floor allowing to turn the handlebars and to pedal. A potentiometer at the handlebars measures the steering angle. A rear wheel tachometer gauges the speed.

A personal computer digitises these informations and transmits them to a Silicon Graphics Personal IRIS 4D/20TG Workstation (since 1988). The workstation calculates the location in the virtual urban space in accordance with the observers´ operations on the bicycle. 14 Meanwhile observers with local knowledge pedal to move themselves in the simulation and try to imagine the real street views they are supported by city maps in their efforts to identify the real urban spaces. These maps are presented by a liquid crystal display mounted on the handlebars: The display presents the biker´s location as a wandering point. 15

Shaw, Jeffrey: The Virtual Museum, reactive installation, 1991, presentation by the artist at the Francisco Carolinum, Linz 1992.

This self localisation of the observer at an installation-external place is substituted in "The Virtual Museum" by a self localisation within the installation´s space.

An observer sits on a chair in front of a monitor. If the observer sitting on the chair moves his body then he activates the monitor projection and a rotable base. On this base the chair and the monitor is mounted. Sensors react to rotations of the chair and movements of its seat-back caused by observer operations. To the sensors´ data in turn react the image projection and the base.

In 1992 all walls of an exhibition space in the Oberösterreichisches Landesmuseum Francisco Carolinum (Linz) were painted with a black horizontal stripe situated circa one meter above the floor. The first virtual space represents this stripe and the rotable base. If the observer uses the chair to navigate himself in the virtual space onto the stripe then it is usable as an interface to four virtual spaces. Three of these spaces refer to art media like painting, sculpture and cinema, meanwhile a fourth space thematises characteristics of computer animated environments via signs ("A", "2", "Z") floating and moving without aim. The floating and jigging signs illuminate the virtual space.

If an observer takes place on the chair-as-interface of the "Virtual Museum" then he looks at the first virtual space as a simulation of the exhibition space including the rotable base with chair and monitor, but without observer. If an observer directs himself in the virtual exhibition space to the black stripe then he recognises it as a switch to further virtual spaces integrating simulations of the exhibition space without the rotable base. For the observer navigating within the virtual space the black horizontal stripe is `readable´ as an indication of a switch function.

Within a sequence of spaces this switch function is a connecting part being only possible in virtuality because it allows to enter a digitally animated space and it is repeated in it as an entrance to other simulated spaces iterating the stripe-as-switch, too: With the switch across the black stripe into the next virtual space the observer is led from the actual virtual space to the next virtual space. Nevertheless this interface within the animation offers no floor plan relating the simulations spatially to each other. The simulated passages represent the passages (doors, wall-openings) in the exhibition space of the Francisco Carolinum to adjacent rooms but the simulations of these architectural elements have no functions in the digital context.

Shaw writes on the availability of an arbitrarily expandable sequence of simulated spaces:

My installation of `The Virtual Museum´ embodies the idea of a single-room museum whose quantity of the virtual exhibition rooms can be infinitely extendend. 16

The installation reduces the arbitrarily continuable sequence of virtual spaces to simulations of spaces reconstructing characteristics of `old´ media. With this "remediation" 17 in three virtual spaces Shaw facilitates himself to expose characteristics of 3D simulations in the fourth virtual space. The four spaces are only a few parts within an arbitrarily expandable sequence of virtual spaces. These parts are enfoldings of a partially unfolded and potentially further unfoldable media development.

At the Institut für Neue Kunst of the Städelschule in Frankfurt the installation "On Justifying the Hypothetical Nature of Art and the Non-Identicality within the Object World" was realised under the supervision of Peter Weibel. The artwork combines four visual worlds conceptualised and programmed by staff members of the Institut für Neue Kunst. When in 1992 the Cologne gallery Tanja Grunert presented the installation an observer walked along a dark corridor to enter a room. It was illuminated by a reactive computer-aided image projection as soon as the floor sensors were activated. Contact mats are set into a floor area of 5 x 5 meters. The incoming visitor has just activated the projection when he is able to recognise the 32 pressure-sensitive elements in the floor and their relations to the programmes of the visual worlds. The observer can activate four coloured floor sensors to select the letters´ projection of the "text world" (Constanze Ruhm/Bob OKane), an "architecture" respectivley "space world" (Dieter Beck/Christian Möller), an "object world" (Akke Wagenaar) or the "gas world" (Gideon May/Laurent Mignonneau).

Weibel, Peter u.a.: On Justifying the Hypothetical Nature of Art and the Non-Identicality within the Object World, reactive installation, 1992. Oberösterreichisches Landesmuseum Francisco Carolinum, Linz 1993.

When an observer enters the installation room then he activates one of the floor coloured sensors located next to the entrance and starts one of the four visual worlds. The observer sees each of these virtual worlds unmodified until he activates further grey sensors. 25 sensors offer the observers to coordinate scaling, proportion and rotation. Further three sensors allow to control twirl, twist and wave functions. 18

Observers can use the floor sensors to influence the virtual worlds in different ways. Especially the "gas world" has a highly developed life of its own and is a specific variant of "artificial life" in Evolutionary Art (see chap. IV.3.1-IV.3.2). Weibel designates the "variability" of self-unfolding virtual worlds as "viability". 19

If observers want to switch between the virtual worlds or to modify one of them then they have to change their distances to the image projection: The activation of the sensors and the observer´s location are coupled to one another. In operating on the technical interface the observer´s attention switches between the body coordination in the real space and the projected space of the image – and vice versa.

Peter WEibel: Zur Rechtfertigung 1992

Weibel, Peter a.o.: On Justifying the Hypothetical Nature of Art and the Non-Identicality within the Object World, reactive installation, Gallery Tanja Grunert, Cologne 1992 (Schuler: Weibel 1997, p.246, fig.113.6).

In front of Barnett Newman´s big lengthwise rectangular paintings with monochrome planes and vertical stripes an observer´s attention switches between the self localisation in the real space (image space) and the space of the image: In displacing himself in the real space the observer tries to find out the best position for a switch into the space of the image. In turning their attention to the space of the image observers switch from a cognitive-corporeal self orientation in the real space with a peripheral visual perception of the picture as an object on a wall to the orientation within the depth effects provoked by the concentration on the visual perception of the colour field with an ongoing peripheral self orientation within the real space. This transition marks the interface between observations of the real space and spaces of the images. 20

Barnett Newman: Cathedra 1951

Barnett Newman and female observer in front of "Cathedra" (oil and Magna on canvas, 244 x 541 cm, 1951) in Newman´s Front Street Studio, New York. Photo: Peter A. Juley and Son. Smithsonian American Art Museum, Washington D.C.
(Anfam: Abstract Expressionism 1990, p.147, fig.110).

The technical interface of the installation "On Justifying..." takes up this switch between the image space (Raumbild) and the space of the image (Bildraum). The technical interface provokes observers to refocusings and reconceptualisations by exploratory motions between the sensors in the real space and focusings of the attention to the spaces of images. The image space/space of the image (Raumbild/Bildraum) switch is the cognitive correlate to the technical interface.

In their efforts to find out which sensors offer to activate which kind of image transforming functions observers switch from a self orientation primary focussed on the real space to a self orientation primary oriented to the space of the image, from an image space/space of the image orientation to a space of the image/image space orientation. If observers construct a cognitive interface for their explorations on the technical interface between real space and the space of the image then it presupposes an inside/outside switch in the relationing of the image space and the space of the image: from the observer´s self orientation within the space of the image as `the inside´ and the orientation within the real space as `the outside´ to the body coordination to activate the sensors within the real space (`the inside´) with an observation of the produced changes within the space of the image (`the outside´), and vice versa. After changing over from one virtual world to another one observers can repeat explorative sequences of actions with refocusings on the image space and the space of the image via inside/outside switch.

The installation "On Justifying..." focuses the attention of observers to the inside/outside switch in a "duo-pluriversum" confronting the observers´ image space with several successively changeable spaces of the image. A model for "world observation" is put on by the operative relation between the technical and the cognitive interface. 21 Weibel bases this model theoretically on an "exo/endo interface" of the observer to the world refering to Otto Eberhard Rössler´s "endophysics" and their concept of an "explicit internal observer":

The virtual worlds are...a special case of endophysics." 22

Dr. Thomas Dreher
Schwanthalerstr. 158
D-80339 München.
Homepage with numerous articles on art history since the sixties, a. o. on Concept Art and Intermedia Art.

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1 Observer operations (physical level: body movements) and observing operations (cognitive level: perceptual schemata, plans for the coordination of actions, self orientation): Dreher: Performance 2001, p.20-23 with ann.12 and 14. back

2 Dinkla: Pioniere 1997, p.72-75; Hansen: Bodies 2006, p.33ss.; Krueger: Environments 1977/1996, p.476s.; Krueger: Reality 1991, p.24-31; Krueger: Videoplace 1985, p.147. back

3 Krueger: Reality 1991, p.43. back

4 Paik, Nam June: Participation TV II, video-closed-circuit, three cameras combined with a Paik/Abe synthesizer and four monitors, Galleria Bonino, New York 1971: Davis: Experiment 1975, p.189; Decker: Paik 1988, p.65s.,151; Kacunko: Circuit 2004, p.187s. back

5 Krueger: Reality 1991, p.105ss. back

6 "The hardware of Videoplace": "...the system consists of two general-purpose computers and a number of highly specialized processors including one that executes forty million instructions per second." (Krueger: Videoplace 1985, p.147)
Most parts of the software were written in C (Dinkla: Pioniere 1997, p.80; Oelinger: Sinn 1999, chap. I: Aktion und Reaktion). back

7 Krueger: Reality 1991, p.48. Cf. Dinkla: Pioniere 1997, p.81; Heim: Realism 1998, p.103; Krueger: Videoplace 1985, p.149; Krueger: Videoplace 1989, p.210,213; Popper: Art 1993, p.113 with ill.190s. back

8 Krueger: Videoplace 1985, p.148s.: "There are approximately 100 states that determine CRITTER behavior...Synthesized sound communicates the personality of the creature." Cf. Dinkla: Pioniere 1997, p.84-87; Kacunko: Circuit 2004, p.235; Krueger: Reality 1991, p.46s.; Krueger: Videoplace 1989, p.210s.; Oelinger: Sinn 1999, chap. I: Aktion und Reaktion. back

9 Krueger: Reality 1991, p.46-56. back

10 Krueger: Reality 1991, p.43. back

11 Krueger: Reality 1991, p.58ss. back

12 Krueger: Reality 1991, p.61s. back

13 Dinkla: Pioniere 1997, p.104-128,132ss.,145s.; Klotz/Weibel: Shaw 1997. back

14 Dinkla: Pioniere 1997, p.115, ann.302. back

15 Cooperation of Jeffrey Shaw and Dirk Groeneveld. Software written in C for Silicon Graphics Computer: Gideon May. Software for a personal computer: Lothar Schmidt. Hardware: analog-digital interface: Charly Jungbauer. Conversion of the bicycle: version for Manhattan: Tatje van Vark; versions for Amsterdam and Karlsruhe: Huib Nelissen (Colpaert/Shaw: Legible City 1990, unpaginated). Lit.: Dinkla: Pioniere 1997, p.114-123; Klotz/Weibel: Shaw 1997, p.126-129,169; Manovich: Language 2001, p.260s.; Paul: Digital Art 2003, p.6s.,72s.; Popper: Art 1993, p.110s., ill.180-182; Shaw: Modalitäten 1989, p.209. back

16 Shaw: Home 1994.
Computer: Silicon Graphics 4D/310VGX. Software: Gideon May. Hardware: Huib Nelissen, Bas Bossinade. Lit.: Dinkla: Pioniere 1997, p.126s.; Dreher: Kunst 1994, p.101ss.; Klotz/Weibel: Shaw 1997, p.132s.,171; Shaw: Museum 1992. back

17 Bolter/Grusin: Remediation 2000, p.65. back

18 The explanation of "On Justifying the Hypothetical Nature of Art and the Non-Identicality within the Object World" is taken over almost verbatim from: Dreher: Beobachter 1996, p.418.
Architecture of the installation: Christian Möller.
The floor sensors are connected by a "circuit board" with the 32 switchers of a "button box": Bob O´Kane.
Coordination of the virtual worlds with the "button box": Gideon May.
Computer: Silicon Graphics 4D/320 VGX.
(Craemer: Rechtfertigung 1992, p.6s.; Möller: Architektur 1994, p.28ss.; Schuler: Weibel 1997, p.288). back

19 Weibel: Welt 1994, p.46,51; Weibel: Kunst 1997. Cf. Hünnekens: Betrachter 1997, p.60ss. back

20 See Dreher: Weibel 1997, p.52s. with ann.62 on Barnett Newman´s explanation of the relation image space ("environment") and space of the image ("sense of space"). back

21 "Duo-pluriversum": Dreher: Weibel 1997, p.44ss.
"World observation": Dreher: Performance 2001, p.27 with ann.24, p.407s. back

22 Weibel: Welt 1992, p.10. Cf. Dreher: Weibel 1997, p.48ss. and Rössler: Endophysik 1992 (Editor: Peter Weibel). back


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