For ASLA/CSLA 2001 LandTech Montreal

Stephen M Ervin
Lecturer in Landscape Architecture
Assistant Dean for Information Technology
Harvard Design School
servin@gsd.harvard.edu

Landscape architecture like the other design disciplines is heavily dependent upon visual presentations, for everything from ideation to construction documents. Historically the vast majority of these have been flat, 2D and presented in a rectangular frame; modest excursions outside of these constraints have been dubbed 'experimental and 'multimedia'. The combination of new digital technologies, research into cognition and perception, and increased awareness of information-management techniques has brought alternatives into the realm of ordinary accessibility. Such presentation techniques range from holograms and QTVR (cylindrical space in a rectangular frame) to fully immersive CAVEs -- environments with virtual images projected on all sides of the viewer, to simulate a spatial experience.

This paper reviews the range of more-than-2D presentation technologies currently available and speculates on some of the implications of their use by landscape architects.

Landscape architects revel in working in the real – ‘natural’ as well as ‘built’ –world. But for reasons of efficiency, safety, convenience and others, we work with models and representations, that are dimensionally scaled and projected, so that they are portable, malleable, and manageable. Most activities – from design ideation and communication to construction documentation – are dependent upon representation.

Historically the vast majority of these representations, other than 3D scale models, have been flat, 2D and presented in a rectangular frame. Drawings in plan, section or perspective are conventionally used to explore and explain landscapes, design concepts, spatial sequences and experiences, and structural systems and details. Several hundred years of convention and experience have led to a rich repertoire of conventional techniques for dealing with these flat, 2D, framed representations. Modest excursions outside of these constraints have been dubbed 'experimental and 'multimedia'. Even Halprin’s radical ‘scores’ are inscribed on ordinary letter-sized paper.

In the past decade or so, the combination of new digital technologies, research into cognition and perception, and increased awareness of information-management techniques has made available a number of representational alternatives, which are not (so) limited to the flat or the rectangular. (Though these attributes pervade almost all of our representational paraphernalia, as we’ll see.)

This paper first reviews the roles and types of representation in ordinary use, then offers a brief survey of the range of more-than-2D presentation technologies currently available, and finally speculates on some of the implications of their use by landscape architects.

The principal role of 2D representation is to make the real world abstract and manageable, so that real attributes and experiential characteristics of the landscape are brought conveniently to the design studio, drawing table or sketchbook. The acts of abstraction and conventional simplification which are required for this purpose – measuring, describing, providing analogues and making use of 2D graphical attributes, among others – have been described and analyzed in the literature on semiotics. The net result is that the present day business of landscape design and planning is heavily dependent upon visual imagery; so much so that some critics have argued that ‘slick drawings’ are sometimes used – sometimes successfully -- to cover up flawed designs.

On the positive side, graphical representation systems make it possible to manipulate "virtual landscapes" (here including ordinary drawings) with multiple design variants, including fantastic and impossible conditions, rapidly and easily. Practitioners, and to some extent lay-people, are able to garner enough visual information from these abstract representations to make judgments about sensation, perception and emotion. Cross section drawings are routinely used to evaluate such landscape perceptual issues as amount of enclosure , or visual sequence. Photographs and movies are routinely used as surrogates to evaluate visual preference for diverse landscape conditions (even if there are legitimate questions about their validity and value.)

Among the 2D images made by designers, three are most commonly used for conveying overall impressions rather than details: plans, plan-obliques including isometrics and axonometrics, and perspective, or eye-level, views.

The choice of viewpoint makes a great difference in the perception of a landscape. A traveler walking through deep woods, along a sinuous path, and finally reaching an open overlook forms multiple reinforcing impressions of the landscape. In digital rendering, you can control the same kinds of impressions by choice of camera angle, position, and other parameters. Three different viewpoints are in common use, and have very different effects: directly overhead (plan), aerial oblique, and eye-level perspective.

The first view, directly overhead, gives a plan view, or a "bird’s eye" perspective. This is a view rarely enjoyed by humans, except in airplanes looking down, and so is the most detached and perhaps indifferent view. It is omniscient, seeing everything, but often objects are seen in unusual ways (trees almost as plan view symbols, buildings dominated by roofs, and so on). In this way, layout and spatial proximity relationships can be best visualized, but the visual aspects of the landscape portrayed may be lost.

The plan oblique is a type of projection drawing that has a high angle of view where one vertical plane has more visual emphasis than the other. The advantage of the plan oblique is that it provides a dimensionally correct or true orthographic plan with the height of elements such as landform, vegetation, and built structures.

The most engaging viewpoint is the eye-level perspective, in which landscapes are seen as they would be from a typical (adult) eye-level view (of about 5'6", or 1.7 m off the ground). In this view nearby elements obstruct further ones, and the view is limited to a cone of vision about 60 degrees wide, so that most of the landscape is not seen at any one time. This is the framed view most likely to resonate with viewers, inducing emotional feelings ‹ of beauty, awe, mystery, suspicion, etc. This view is also the one most influenced by lighting, shadows, and atmospheric effects. From a modeling and rendering perspective, the eye-level view allows the most potential economy, as only visible elements need to be modeled, and selective levels of detail can be employed. Naturally, one would usually model a bit extra ( if not the whole scene ) so as to be able to shift the viewpoint around to find the very best.

The same basic views used for static visualization ( plan, oblique, and eye-level ) can be used alone or in combination, in dynamic animations as well. Many landscape scenes are large enough that an animated view (a walk-through or flyover) is the best way to illustrate all of the landscape. In addition, landscapes are often experienced in motion and these representations can be used to simulate that experience.

It’s obvious that choosing the right view is important in making these representations, but choosing the right frame may be equally important.

Framing a picture is an essential part of the composition process. Choosing between landscape mode (a rectangle with a longer horizontal axis), portrait mode (a longer vertical axis), or even a perfect square, is a first step. Many landscape images naturally look best in a ‘landscape’ format. Historically, two aspect ratios have dominated landscape visualizations: the 3:2 ratio of 35mmslides, and more recently the 4:3 ratio of most computer display screens (640 x 480 pixels in early models, 1024 x 768 or 1600 x 1200 more recently). This latter rectangle is not really very elongated, and so some landscape representations have tended for even more extreme aspect ratios, such as 8:3, so that two frames fit vertically in a standard computer window. The advent of high definition digital television (HDTV) has brought its new standard aspect ratio of 16:9 (nearly 2:1) into regular use, a format more suited to landscape scenes (and large movie screens). I am unaware of any literature on the impact of the frame upon landscape perception, but intuitively there is some. Certainly, the act of framing serves to both emphasize, and to hide, in the same way that all abstraction does; in addition, the act of framing introduces the visual elements of balance and proportion.

For many landscape architects, the first step to breaking out of the frame has been the ‘two-slide’ presentation. Using two side-by-side 35mm projectors, two images can be juxtaposed for two important purposes. One, the illustrative or pedagogic, is to show two images at once for the purposes of comparison or contrast. The second, is to create a wide-angle panorama view – usually of a landscape scene – created by taking two pictures side by side with a very small overlap. (If the projectors and screens can be moved to accommodate the overlap, that is ; otherwise, ideally, you want no overlap, just two images exactly adjacent – a condition almost impossible to create with a hand held camera and ordinary lens.) Some have even used a three-screen panorama to emphasize majestic landscapes.

The goal of these efforts is to provide more information in the field of view – to create a more synoptic view. Also, critically, as the field of view widens, the human peripheral vision system is brought into play. And finally, if the image is large enough that the human head or body has to move to take it all in, the whole range of kinesthetic experience may be brought to bear. In this way, these systems engage, in Howard Gardner’s terms, not just "spatial intelligence", but also "bodily-kinesthetic" intelligence as well.

The science of immersive display systems ,which has developed in the last decade in conjunction with the Virtual Reality research enterprise, has led to the development of a number of computer-aided techniques to further expand upon displays which engage these bodily senses and perceptual systems.

In these new systems, the frame is dissolved, at least partially, and landscapes are able to be viewed, or experienced, in a more encompassing and engaging way. These systems generally replace the rectangular picture plane with a cylindrical or spherical viewing surface, which may be constrained to being accessed through a rectangular portal, but which can contain more and can be experienced in more immersive ways.

The original "frame-breaking" visual technology was holography, in which convincing 3D images are created by the use of stereoscopic photography and special laser films, which create the illusion of spatial depth when viewed from a specific angle. This illusion, since it is based on actually stimulating the separate visual fields of each eye in the viewer, is compelling. 3D objects literally appear to "reach out" from, or recede into, the framed image.

Holograms have most often been made of "objects", such as human heads or physical things, and the use of holography to document landscapes has snot been deeply explored. (Also, the technology remains somewhat exotic, and is not easily incorporated into ordinary desktop computing or photography.)

An alternative way of creating more 3D images uses special eyeglasses, which vary the image being received by each eye, so that the two images can be fused to create a 3D perception. One variant uses simple Red-Blue filters to create two separate images, but these are relatively crude in their ability, being primarily limited to wireframe cartoons. More sophisticated are "shutter-glasses", which use a moderately high-frequency (above 20 Hz) shutter to alternately receive images in one eye and then the other, synchronized with a special projector or CRT which also alternates images at the same frequency. This technique can create quite convincing 3D -- still within a rectangular frame -- very much like a hologram. The big disadvantage is the need for special glasses which must be tethered by a wire to the display device.

For most people, the most familiar field-of-vision-filling experience is the IMAX (or OMNIMAX) movie, a presentation made using oversized film , special projectors, and "surround-sound" audio speakers in a large-diameter (30'-80')domed presentation space (often a planetarium, now special purpose theaters.) These domed screens create an image that fills the viewer's field-of-view, and can create a strong immersive sensation, such that the environmental experience is much more 'physical' than in ordinary cinema. In these films, mostly of the "edu-tainment" variety, each viewer is usually solitary as in an ordinary movie; the shared environment is not much capitalized upon, and each viewer's awareness of neighbors is minimized.

The same principle as used in the IMAX displays has been modified for smaller one-person or small-group projection environments. The use of a spherical display surface allows the projection to feel immersive, but also requires special software to suitably distort the image so that the projected image appears in correct perspective. These display systems are becoming popular with product design teams, as they enable 3D mockups to be evaluated without building real 3D models. Their applicability to landscapes has not yet been extensively tested.

A computer based format for presenting landscapes is the animated panoramic view presented by Aple Computer's QuickTime Virtual Reality or QTVR format. This provides 360° cylindrical view, around a fixed viewpoint, which can be interactively "panned" by the viewer on an ordinary computer screen. Although the portal is still a rectangular frame, the sense that a "complete landscape" lies behind it helps to minimize the constraining effect of the frame. These QTVR format images can be constructed by stitching together a series of photographs, taken in a 360° circle, using special-purpose software, and some modeling systems can directly export QTVR format. QTVR also allows for embedded "hyper-links" so that portions of one scene can be linked to another QTVR scene, much like rooms connected by doors, adding to the illusion of a "boundless" space.

Other Virtual Reality (VR) display systems use special head-mounted displays (HMDs) to create a stereo view by projecting two synchronized images directly in front of each eye of the viewer, and use motion tracking hardware and software to change the viewpoint of the scene as the viewer’s head moves, from side to side or up and down. This can give the illusion of being inside a virtual landscape. These systems must create real-time imagery, at up to about 30 frames per second, and so usually have very simple, and highly stylized contents.

The constraints on these systems include available resolution (thousands of pixels per eye), and the weight/comfort factors of the head mounted apparatus. In these systems, no awareness of other participants or ambient cues are possible, since each eye is completely covered. HMDs have been extensively explored for very expensive, high-tech, industrial/military systems, such as flight training simulators, and are also available for more modest 'VR' uses. Their ability to display landscapes is still constrained by the ordinary rectangular display presented to each eye.

In these kinds of immersive display environments, an image is displayed on a screen or series of screens completely encircling the viewer, from 180° to 360° around, so that wherever the eye is looking, the peripheral vision, outside of the normal 60° cone of vision but very important to our perceptual sense of context and continuity, is engaged. This requires between 6 and 24 individual projectors, each projecting an overlapping, carefully synchronized image. While the software for synchronizing the images from projectors is relatively exotic, these systems are otherwise fairly easy to mount and create imagery for.

For static images, this is no more than the two- or three-screen slide show reproduced digitally. The great value comes when animation and interaction are added. Then, the experience of walking in, driving through, or flying over a landscape can be well evaluated. As the viewer's eye position moves, a new image is generated for each screen, and the three or more projectors are simultaneously updated, giving the illusion of smooth motion through the landscape. (In high-end entertainment theaters, this is enhanced by having chairs with hydraulic controls so that the whole body an be lurched, bumped, and tilted as part of the "ride.")

Creating the 3D model for such systems is no different than for any other rendering or animation system. The special technology required is the synchronized update of the projectors, coupled with some tracking device -- mouse, or hand-held wireless pointer, etc. -- that guides the motion. Then the navigation through the model can be driven by one or more of the participants/viewers.

This kind of display, which places the human body physically immersed in the virtual landscape, and has the landscape appropriately sized larger than the body, is the most evocative in terms of evoking real kinesthetic awareness of the landscape. Coupled with the engagement of peripheral vision, the sensation of containment is quite convincing. While there may be more outside visual cues that enter than with the closed system of the HMD, for example, the human eye/brain combination is quite good at filtering these out, in support of the illusion of virtual space.

The most exteme variation of the surround-screen environment is the so-called "CAVE" visualization environment, in which a cubic volume of space has images projected, usually from the rear, on at least four surfaces, and up to all six surfaces including floor and ceiling. CAVE systems require the most demanding hardware, software, and presentation spaces, as well as special model formats. For real-time animation, as used in scientific visualization , massively parallel computers may be required to generate the 4 to 6 simultaneous images. CAVE systems are sometimes augmented with shutter-glasses or other techniques, including haptic force-feedback systems, for extending the "virtual reality" of the immersive experience. CAVE systems, which are currently in active use for scientific as well as architectural visualization and simulations, requires more computers, cameras and projectors than any of the other systems, but also may increase the immersive sensation and the robustness of the virtual environment so created.

These latter systems -- multi-screen and CAVE environments, offer the most promise for landscape simulation and evaluation for several reasons. The landscape is inherently large, and so the larger the display space available -- up to a full 360° display sphere -- the better. Landscapes are also inherently horizontal, so maximum display space in the x-axis is desirable. And most people's landscape perception has a kinesthetic element, so to the extent that the peripheral vision system, and "whole-body" perception can be engaged, the more likely that the simulated experience may correspond to the actual.

Judging landscape space, such as in plazas and open areas, or environments with long views, is much more satisfying in an immersive display, since the "human scale" factor is more easily engaged than with a typical framed view.

The ability to engage with several others in experiencing a space adds both to the verisimilitude of the landscape simulation, but also to the ability to share communications, and to discuss perceptions, etc. Thus, for evaluating landscape designs in a presentation, several people in an immersive display really is the "next best thing to being there." This shared group experience may be on eof the most compelling reasons to employ these immersive environments, as then the whole range -- or at least a useful subset -- of human social and behavioral issues can enter into the experience. Landscape perceptions in the environments are not just visual, though of course the visual is important.

Once you have stepped through the window, into the environment beyond -- broken out of the frame, and into the landscape -- you will not want to go back.

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