Automatic generation of 3-D building models by straight skeleton

A 3-D city model as shown in Figure 1 is important in several fields, such as urban planning and gaming industries. However, enormous time and labour has to be consumed to create these 3-D models, using 3-D modeling softwares such as 3ds Max or SketchUp. For example, when manually modeling a house with roofs by Constructive Solid Geometry (CSG), one must use the following laborious steps: (1) Generation of primitives of appropriate size, such as box, prism or polyhedron that will form parts of a house (2) Boolean operations are applied to these primitives to form the shapes of parts of a house such as making holes in a building body for doors and windows (3) Rotation of parts of a house (4) Positioning of parts of a house (5) Texture mapping onto these parts.