The Language of Terrain Ian JØRGENSEN 1 Introduction To understand one another at least two conditions should prevail; people participating in a communication should speak the same language and there should between them exist a fair level of shared experience and culture (SORVIG, 1996; EATON, 1990). New information technologies have produced new languages to interact with (design) and represent the landscape and these of course influence the communication. Following Alan MACAECHREN (1994) one could distinguish between two situations where new landscape languages might have an impact. One is the role of visual communication the other of visual thinking. Although he writes about cartography and addresses his article to geographers and other map users these two roles apply perfectly to those of landscape design. Visual thinking is characterized by being a private activity, revealing unknowns and based on a high computer-human interaction, whereas visual communication is characterized by the opposite (public activity, presenting knowns and often at a low computer-human interaction). In the first case a designer is struggling with his design in heavy interaction with the map (intelligent software), in the second he is producing images that could explain and communicate the main points of at this stage his finished design. The literature shows that there is an extensive research interest in visual communication (ERVIN and HASBROUCK, 2001; BUHMANN, 2003; LUP, 2001) whereas visual thinking appears to be a rather neglected area within digital landscape design. The focus in this paper is a landscape architect sitting in front of a computer with intelligent landscape software installed (Civil 3D). He is about to create a design for the areas around the new Opera in Copenhagen. In an introduction to the software it is described as an easy-to-use design and drafting program that supports a wide range of civil engineering tasks (AUTODESK, 2005). The software developers in this statement touch a central theme in the definition of landscape design, because some regard engineering as an activity that succeeds a design, whereas others (LYNCH, 1984; STROHM, 1998) regard it as an important part of design. This paper takes the latter point of view and analyses to what degree the software combines the two cultures, design and engineering, using the example of the Opera.
I. Jørgensen Shared language Shared culture Landscape architect Contours Design Terrain software Triangulated net (TIN) Engineering Fig. 1: Conditions for intelligent landscape software to work: The success of terrain software used for design (visual thinking) depends on the degree of overlap in language and culture between software and designer. In design of roads, the software has shown its usability. Compared to this the opera implies a more open design process, which is non-serial, not based on predefined aesthetic criteria and with few constraints to the final form of the terrain. Beside common culture, the second condition for the landscape designer to understand and incorporate engineering tasks would be that he speaks the same terrain language as the software. In the pre-digital era most landscape architects analysed, and expressed landscape terrain intentions by using contours, spot heights, and cross sections. As this is still the case, landscape architects native language of terrain is contours, which is only the second language of the software that operates on a triangulated net (a TIN). In the following visual thinking (design) based on intelligent digital software is compared to analogue design asking how the software influences terrain language and to what extent it bridges the gap between design and engineering. 2 Visual thinking - background The first wave of landscape software turned the computer into a drawing machine. The second wave of software had data attached to graphic objects and thereby became intelligent. Instead of a set of drawings from each part of the construction sector, an intelligent model was now accessible to anyone in the building process. The model comprises objects that contain information about themselves and maybe also about other objects in the model. In landscape architecture an object could be a tree with data attached about its growth rate, 3D-shape, species, prise, maximum height and maybe design requirements as distance to drains and cables in the ground.
The language of terrain in design and communication Tree drawn by hand Tree drawn on plain CAD Object-oriented tree No comments Centre: 5.34,6.48 Radius: 4.5 drawing units Layer: Trees Fig. 2: Species: Quercus rubra Growth rate: slow Maximum height: 24 m. Size: 30-50 cm Prise: 9,56 Kr. Etc. Object-oriented design. What do you know about yourself? The analogue tree is mute, the plain CAD tree knows about geometry and the intelligent tree knows what is stated in the database. It is not as straight forward to model with objects in landscape architecture as in architecture/construction. A window has a certain form and position in the wall and will in most cases be copied and repeated. A tree on the other hand grows over time and is influenced by the position of other trees, thinning, stress factors etc. Areas of grass or hard surfaces each have their form, and therefore cannot be repeated. And the terrain itself is amorphous. The software used in this research Civil 3D is dynamic and based on a central terrain model that carries all information about the terrain. In this article, using civil 3D or similar software is referred to as intelligent terrain modelling. This corresponds to what architects call object-oriented design. 3 Visual thinking establishing the model Fig. 3: The Opera in Copenhagen Built in 2005
I. Jørgensen The Opera in Copenhagen is designed by Henning Larsen as architect and Schönherr as landscape architect and was built in 2005. It is situated on a very significant site on the harbour front located directly opposite the Royal Palace Amalienborg. The island on which the building lies is about 100 meters wide and is artificial which simplifies the terrain work, as there is no existing terrain to consider. Elevation differences are about 1 meter. Even though there is no existing terrain, some existing conditions bind the design. The glass part of the building façade should connect to the terrain at an elevation of 3.30 meters and adjacent bridges connect to the island at 2.65 meters. On top of the steps by the water-front the elevation is 2.52 meters. As a design concept the floor elevation inside the glass façade is extended through this, and then gradually sloping towards the site boundaries (fig. 4). Up to this point digital and analogue design are pretty much the same, but now they follow each their path. In analogue design the next steps would be to sketch and then place the contours using calculations as shown in fig. 10. Each time an external condition or design idea changes, contours would have to be recalculated. To help envisage the form, cross sections would be constructed, and each time one or more conditions change, cross sections would have to be reconstructed. In digital terrain modelling the next step after stating the design conditions would be to enter these conditions including design intentions into the model in this case fixed spot heights (at bridges), contour parts (glass facade) fixed slopes (adjacent to facades) and slopes of an unknown but even grade (to the site boundary). From these a TIN would be produced (fig. 5) and if requested contours could be drawn. In analogue design contours are used as the language to interpret, analyse, calculate and envisage the terrain, whereas in digital design a model is built not from contours but based on design conditions and intentions, and it could be changed not by changing contours but by operating on the design conditions or intentions. Fig. 4: Design conditions and main idea Fig. 5: The resulting TIN Design information is inherent in a digital terrain model as opposed to an analogue drawing where it might be found as text beside the objects or in the mind of the designer. If, as an example, the architects suggest lowering the façade 7 centimetres, then the facade line is
The language of terrain in design and communication lowered 7 centimetres, the two offset lines are automatically recalculated, the TIN updated and new contours could be extracted. Because everything builds on one model, all output representations, besides expressing the theme asked for, function as a model check. If, for example, a contour map turns out like the one in figure 6, obviously one point is incorrect. As the model is dynamic the contours will be adjusted as you lift the point or type in the correct elevation. Any other derived information or connected design elements would at the same time be adjusted e.g. an elevation map, a vertical profile or a cut and fill calculation. Fig. 6: Contours reveal a model error Fig. 7: A point is moved and the error fixed 4 Visual thinking shared culture? The model of the opera terrain can be represented in a number of ways which are not available in analogue design. Two examples are shown below. In the first, slope arrows are drawn indicating slope levels between 0.5 and 1.5, 1.5 and 2.5 and above 2.5%. First of all the designer can conclude, that the water is running in a direction away form the house, secondly the arrows invoke some aesthetic design questions. Apparently the bridges are located so low in terrain that a slope from bridge to building is steeper than at the two adjacent sides. Will this be visible on-site? Would it then be better to let the terrain fall at a fixed slope? Along the right side of the building (fig. 8) slope arrows shift in direction indicating an edge which do not match the design idea of an overall falling terrain. The second illustration (fig. 9) shows a cross section along the southern (left) boundary of the site. At the moment the data it builds on includes only 5 points. Experienced in an eyelevel perspective view such a terrain will produce visual breaks where there are too big shifts (differences) in slope. To avoid this, transition curves are inserted (see lower part of fig.9) to produce a smooth terrain. Points from the redesigned vertical alignment are transferred to the model of proposed terrain. To check the result one might view proposed contours and see if any areas have a slope of less than 1%. And a water catchment map, for example, could illustrate which areas need to be drained.
I. Jørgensen Fig. 9: A vertical alignment on the left (south) boundary of the site. On top: alignment is extracted from existing terrain and only contains few points. Below: transition curves are added. Fig. 8: Slope arrows: direction and intervals: light 0,5-1,5%, medium with white border: 1,5-2,5%, and dark: over 2,5%. Only parts of the site are illustrated see text. 5 Visual thinking shared language The digital language of terrain contains a series of signs (functions) as spot height, contour, 2D and 3D line, daylight line, grading object, slope or break line. These signs can of course be drawn by hand but the radical difference lies in the fact that the digital model is intelligent and the paper is not. Signs in the digital model can form sentences, replace each other and be translated into another language as illustrated in the example of the opera where spot heights, contours and slopes were encoded in a TIN and then again presented as contours. Compared to this the analogue language is rather poor. As the illustration indicates the signs (here spot heights and contours) need a translation (lengthy calculation) to interact.
The language of terrain in design and communication Analogue terrain design Digital terrain design Spot heights, 3Dlines, breaklines, contours, slopes, daylight lines, grading objects, vertical alignments Fig. 10: Analyses of elevation, slope, orientation, water catchment areas, calculation, cut and fill, visualization, Left: When operating on paper, it takes a while to calculate contours from spot heights. Illustration from STROM and NATHAN (1998). Right: In digital design the TIN-language offers an extended terrain vocabulary expressing design intentions and including terrain analyses, calculations and visualisations in the design. If an analysis leads to design corrections, these can either be done by TIN corrections or by adjusting slopes, breaklines etc. Actually, the contours for proposed terrain at the Opera did not turn out as smooth as indicated until now. Figure 11 shows contours as they appeared and figure 11 explains why. The TIN is produced on algorithms that will minimize the length of the triangle edges (Delaunay triangulation, ERVIN, 2001). The result (fig. 12 left) is a series of triangulation points along the site boundary each of which is producing a sub-transition that turns out to produce angular contours when they are put together. At the right side of fig. 12 this is changed by swapping edges in the TIN in a way that one central corner (upper right) is becoming the centre for most tin edges producing an overall transition from vertical to horizontal curve directions.
I. Jørgensen Fig. 11: Contours as they turned out to be as a result of design conditions (fig. 4 and 5). Fig.12: The triangulated net explains why contours turn out the way they do (left part of fig 12). When swapping lines the net is changed and so are the contours. By adding this in-between adjustment of contours through TIN a second design instrument has been introduced (see fig. 10 arrows to the right). It cannot be avoided and therefore the designer has to learn the language of the TIN. In this case, edges in the TIN had to be swapped to get a smooth transition. In other situations vertexes in the TIN would be moved and new points added or moved. Each decision is automatically followed by a contour response, which helps to interpret what has happened. If, for example, the shoulder leading from the glass façade to the upper right corner could be minimized (as a design option), then the upper right point should be moved to the light spot, and contours would illustrate the result. Unexpected contours as a response to design conditions can be regarded as bad communication (students would say a lousy programme). In most cases though it can be seen as a very precise answer to unclear design intentions. In our example the designer just stated as a design condition that the terrain should fall towards the boundaries, and the answer was: in what way do you want it to fall? Like this (showing TIN and angular contours)? Another example could be that a very simple and strong design idea turns out to cause a lot of trouble when meeting the edges of the site. At the Opera, an evenly sloping terrain from the waterfront would for example create design problems when meeting the glass facade because the slope has to end at 3.30 in different distances from the starting line. But as in the example above edgy contours would show the case and ask for detailing. 6 Discussion and conclusions Through an example this paper explores the conditions for digital terrain modelling as part of a landscape design process. The main emphasis is on visual thinking as opposed to visual communication and the approach is structured by the idea of software being a
The language of terrain in design and communication language which opens for a possibility to compare digital and analogue interaction with terrain. It is found that terrain software provides the designer with a language that in many ways outclasses the analogue one. First of all it embraces a series of terrain signs (contours, spot heights, 3D-figures, grading objects etc.) where the analogue language is a single word one. Secondly, intelligent software provides the landscape architect with a language of terrain in which he can express his intentions of design and operate on these, opposite contours which are not expressing intentions, but derived information. Thirdly, intelligent software opens for terrain analyses that are unreachable in analogue design; analyses that not only concern engineering (calculation) but also question aesthetic decisions. Ultimately this might change the design process (JØRGENSEN, 2004). At the operational level this depends on the landscape designer s willingness to accept and learn the TIN as at least a second language. A TIN is a product of input data, mathematical rules (e.g. shortest line triangulation) and operators (e.g. minimize flat triangles). To a certain extent these functions are developed for building technical terrain. To make it more suitable for general design purposes more signs and operators should be developed, for example; S-formed slopes that would distribute points along a slope (triangulation) according to a more smooth form, or drainage points which like a magnet would be the centre of triangulations. The conclusions in this paper build on one single design example which in many ways is not characteristic for landscape design in general. Normally you would find bigger differences in elevation, but even so the principles would be the same, and as Strohm (STROM, 1998) expresses it the intent to change a grade 2 inches is no less important than the intention to change a grade 2 feet. Likewise, in most design the proposal would reflect the existing ground conditions, but in this example the intricate relations between existing and proposed terrain were skipped to focus on language and keep things simple. It is worth while mentioning though, that intelligent software includes functions for grading and daylight lighting which introduce a dynamic relation between the existing and proposed terrain. In one way the Opera example characterises most landscape terrain projects and that is by dealing with an organic terrain. This was chosen to (con-)test the TIN. Project like Fossar de les Moreres or Jardin Botanique at Mont Juic in Barcelona would not have evoked any linguistic discussion as they appear to have been designed without contours. The first one as spot elevations along buildings, and with an edgy depression in the centre and the second as a hillside TIN where some vertexes are elevated and adjacent ones lowered to form triangular areas for sitting and relaxation. These examples are probably not produced with terrain software, but they appear as if they were, raising the question if terrain software on top of analysing the aesthetics of existing design will introduce a new aesthetic.
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