| Research Abstract |
Based on features on digital map, such as building contour (building polygon) and road polyline, we are proposing the system to generate 3-D Urban Model automatically. A 3-D urban model is an important information infrastructure that can be utilized in, several fields, such as landscape evaluation, urban planning, disaster prevention simulation, tourism, and many other business practices. In addition, disclosure of information about public projects to the public in order to encourage their participation in city planning is a new application area where a 3-D urban model can be of great use. When a real urban world is projected into 3-D virtual space, buildings are major objects in this space. To realize a 3-D urban model, it is important to generate building models efficiently. However, in order to realize 3-D building models, enormous time and labor has to be consumed to acquire the spatial data and to design the models. For example, when manually modeling a house with roofs by Constru
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ctive Solid Geometry (CSG), one must follow these laborious modeling steps : 1)generation of primitives of appropriate size, such as box, prism or polyhedron that will form parts of a house 2)boolean operation among these primitives to form the shapes of a roof and a house body 3)rotation of parts of a house 4)positioning of parts of a house 5)texture mapping onto these parts.
In order to automate the steps mentioned above, we proposed the GIS and CG integrated system that automatically generates 3-D building models from building polygons on a digital map stored by GIS. Most building polygons have right angles (orthogonal polygon) and varies in the number of the vertices. The algorithm for dividing orthogonal polygon into a set of rectangles is developed. After dividing, the integrated system is placing CG primitives i.e. building parts on these polygons to form a 3-D building model. The system automatically generates a 3-D urban model so quickly that it meets the urgent demand to realize another alternative plan.
Also, we propose the automatic generation system to produce 3-D water way model from a center line of water way stored and controlled by GIS. The water way that restores native habitat and its natural meander plays an important role for the revitalization of a city. The water way improvements project aims to provide stable, maintainable flood control while environmentally restoring sections of water way to their natural meanders and adding amenities and recreational opportunities along the water way. In these projects, 3-D water way model will serve as planned or proposed common image among citizen, neighborhood, designers and officials. However, in order to realize 3-D water way model, enormous time and labor have to be consumed to design bank, shore, vegetation and topographical features. In our research, we developed the system to generate 3-D water way models, automatically by integrating GIS and CG. Less
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