Information technology is continuously pushing the limits as a tool for designers. At the moment, architects around the world struggle to implement digital strategies based on Building Information Models (BIM) to replace previous strategies based on drawings. A BIM is a digital representation of buildings, containing both graphic and numeric information of the objects, such as walls, windows and stairs, which make up the architectural project. The model appears in 3D and the designer operates in this spatial environment to add and edit objects.

Not only the built environment, but also terrain is a target for model-based design, leaving engineers and landscape architects in the same situation as architects and building constructors. Instead of working on a BIM, these groups operate on a LIM - Landscape Information Model. The software for modelling the terrain has been on the market for many years, yet only sparsely implemented in terrain design.


Figure 1: A simple way to interact with a LIM - a Landscape Information Model - is by editing the surface and analysing/ visualising the results.

Basically, modelling requires a designer, in this case a landscape architect, and a model visible through a software interface. The software includes some tools that allow the designer to construct and edit the terrain-surface, whereas other tools make it possible to visualise the consequences. In the process of design there is a direction to this, as new ideas are built into the model and consequences are visualised in one of the many ways model data can be envisioned. In many cases the visualisation reveals unforeseen consequences, which call for new ideas or detailing, and hereby the “dialogue” is established (fig. 1).

This basic description of interaction with a surface model becomes more complicated should it cover the two situations where the designer collects in-data and produces final presentations (fig 2). The modelling tools for creating an existing terrain in the software are to a certain degree different from the tools for developing a design on the terrain and tfor editing the design. This can be illustrated by dividing the terrain building tools into two blocks, where one represents in-data for creating an existing ground, and the other stands for modelling tools for creating a terrain design.

Likewise, the instruments for visualising the model data can be separated into two, depending on the purpose of the visualisation. Up to this point, the focus has been on the designer, who is in a close dialogue with the model, testing the ideas and perhaps trying to reveal the unknown possibilities in the site. This situation is considerably different from the one where a final presentation is produced and the data is presented for an external audience.
 

There is still a direction to the work process; in a very simple case it takes a single turn from in-data that build up an existing terrain, which can be visualised, edited and turned into a costumer presentation.


Figure 2: Collecting surface information and presenting the results.

Most design processes are not this simple; instead, they are developed through a series of stages. In the article "Stop drawing start modelling" there is a description of how the model can be implemented for inventory, design development and design implementation. The further ahead one reads, the more obvious it becomes to work on the model, yet the article indicates that even in the early stages the model can be applied to express general ideas of the design, for example as 3D-sketches (fig. 3).


Figure 3: The model is detailed through the design process.

To keep the illustration simple one important parameter is omitted; it is the interaction with other parties of the building process. At all stages of design development the landscape designer will exchange surface data with others, for example to ground the buildings and make storm-water run into drains and pipes.

A common, yet wrong interpretation of model-based design is that the software takes over the design process by giving the answers. In a very narrow scope this point of view can be defended because the design intentions, once built into the model, are dynamically linked to a 3D-appearance and a series of analytical visualisations. However, for this to work two prerequisites should prevail. Firstly, the design intentions should be grounded and not just casual, and secondly, the visualisations should give meaning to the one interpreting them.

In other words, for the technology to work, the operator should be able to develop design intentions and possess knowledge to interpret the outcome in form of perspective views, terrain analysis or calculations. This is illustrated below. The designer’s capabilities cover a wide range of issues, where some are operational (getting ideas and transforming them to specific intentions) and others are based on knowledge and aesthetic values.

Figure 4: Knowledge about terrain is a prerequisite for landscape design.

The website you are currently visiting, "Terrain Modelling in Digital Landscape Design", is organised in 6 sections corresponding to the described understanding of the design process. Beside the four subjects that surround the simple modelling loop (transforming in-data to an existing terrain, visualisation and analysis including calculations, such as cut and fill, modelling a proposed terrain and communicating the result in final presentations), two more subjects are added. One is about how to organise the process named 3D-work-method and the other is about the subject specific knowledge and capabilities, which are essential to make the whole system work. At the moment, this last evasive subject is named Design and Technique. When more articles and possibly tutorials are added to this field, it might be subdivided; until now we leave it open.

Figure 5: This web-site is divided in 6 parts according to the described process- model of design.  Parts of the process are A) in-data: Creating and adjusting a model, B) Analysis, C) Modelling and D) Presentation. E) 3D-work-method is what holds the parts together and F) Terrain knowledge is what initiates the interaction and gives meaning to the views on the display.