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PROCEEDINGS OF THE SEVENTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY
Edited by: B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru and M.L. Romero
Low-Budget Three-Dimensional CAD Visualization of the Athens National Garden by Merging Heterogeneous Data
I.E. Tzouvadakis1, A.A. Stamos1 and D.I. Vassilaki2
1School of Civil Engineering, 2School of Rural and Surveying Engineering,
I.E. Tzouvadakis, A.A. Stamos, D.I. Vassilaki, "Low-Budget Three-Dimensional CAD Visualization of the Athens National Garden by Merging Heterogeneous Data", in B.H.V. Topping, J.M. Adam, F.J. Pallarés, R. Bru, M.L. Romero, (Editors), "Proceedings of the Seventh International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 77, 2010. doi:10.4203/ccp.94.77
Keywords: computer-aided design, visualization, three-dimensional modeling, architectural, digital terrain model, heterogeneous.
The hand-crafted technique of a maquette is a timeless tool in architectural design. This technique offers the opportunity to survey the earth's surface in the natural way similar to the way the human sight is working, without demanding specific interpretative knowledge of the classic engineering designs. However, disadvantages of this hand-crafted technique, are the required time to obtain the essential materials (paper, wood, etc.), the cost of materials, the time needed to sculpt the model, the specialized personnel, and the difficulty of carrying the model to different places for cooperation or presentation purposes. These disadvantages are overcome by the use of digital visualization techniques (digital maquette).
In this paper, the procedure developed to create the digital maquette of the National Garden of Athens is presented. The National Garden of Athens is a 170 years old park in the center of Athens. Its renovation is subject of an interdisciplinary research project coordinated by the National Technical University of Athens. To enable cooperation, the necessity of a three-dimensional CAD digital model of the garden arose. However, due to the low budget restrictions and time limits, it was necessary to use the existing tools and existing heterogeneous, and incompatible (at first sight), data whose main characteristics were the multitemporal character and their compilation in various coordinate systems. The available data for the visualization were: (1) 3D points collected with geodetic and GPS measurements, (2) a large scale digital topographic map, (3) four, old, medium scale, overlapping topographic maps on paper, (4) a two-dimensional digital map of the location and species of plants, (5) a catalog of the tree species with information about shape and dimensions. The available tools for creating the map were the CAD software, namely AutoCAD, an in house built topographic software, and custom free software.
The general outline of the procedure for the three-dimensional digital maquette creation, was to ensure that the data was in the same coordinate system, to extract the topographic points, and compute the contour lines. Then, to create manually, with AutoCAD, three-dimensional terraces between the contour lines, which represented the terrain of the garden. The three-dimensional model of each species of trees were then created manually with AutoCAD, and all the trees were "planted" automatically to their three-dimensional position, computing the z-coordinate using a digital terrain model. Several photorealistic three-dimensional views from the garden were then produced, and the area covered by the trees was computed using custom methods.
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