Method for automatic modeling of complex buildings with high accuracy

A high-accuracy automatic 3D modeling method for complex buildings, comprising the steps of:

• reading and preprocessing data of a building;
• wherein the data of a building includes architecture blueprint, working drawings or as-built drawings;
• wherein in the reading and preprocessing step, the data of the building are acquired by reading a file containing the data of the building with specific software and the preprocessing involves checking topology, merging adjacent points, normalizing object attributes and assigning elevation values over the data of the building;
• wherein in checking topology processing step, nodes of a simple polygon are sequentially connected clockwise, nodes of the exterior boundary of a complex polygon are sequentially connected clockwise, but nodes of the interior boundary are sequentially connected anticlockwise;
• extracting information for modeling from the preprocessed data;
• and
• modeling a main body and a roof of the building by using the information for modeling acquired in the extracting step;
• wherein the main body of the building is modeled based on plane coordinates and elevation data of a boundary of the building acquired from the information for modeling;
• wherein an order in which nodes of the boundary of the building are plotted in the information for modeling is rearranged and then input to a 3D engine for modeling;
• characterized in that the roof is modeled by determining the shape of the roof based on the plane coordinates of the boundary of the roof acquired from the information for modeling, processing the boundary of the roof based on the determination, and modeling the roof based on the shape of the roof and the elevation data without addition of nodes of the boundary;
• the modeling of the roof of the building comprises the following steps:
• identifying the roof boundary of the building;
• determining whether the boundary of the roof of the building is a simple polygon or a complex polygon;
• and
• if the boundary of the roof of the building is a simple polygon, automatically dividing the simple polygon into a plurality of triangles by using a method for simple polygon division to acquire information for modeling the roof;
• or
• if the roof boundary of the building is a complex polygon, dividing the complex polygon into a plurality of simple polygons by using a method for dividing complex polygon and then acquiring information for modeling the roof by using the method for simple polygon division of the above step;
• wherein the method for simple polygon division comprises the following steps:
• determining whether the number of nodes of the simple polygon is three;
• if yes, indicating that the polygon is a triangle, inputting the information for modeling the triangle to 3D engine;
• otherwise, traversing all the nodes of the simple polygon;
• selecting any two non-collinear nodes on the exterior boundary of the simple polygon;
• connecting these two non-collinear nodes if a straight line connecting the two non-collinear nodes:
• (i) does not intersect with the exterior boundary, and (ii) has a midpoint located within the polygon, otherwise traversing another pair of non-collinear nodes on the simple polygon until two non-collinear nodes that meet the requirements of (i) and (ii) are found out;
• dividing the polygon into two parts by the straight line connecting the two non-collinear nodes to obtain two new simple polygons;
• repeating the above steps to divide the new polygons until the number of nodes of each of resulting simple polygons is three;
• wherein the method for complex polygon division comprises simplifying the exterior boundary and simplifying an interior boundary, wherein the method for simplifying the exterior boundary further comprises the following steps:
• simplifying the exterior boundary of the complex polygon and dividing the complex polygon into a plurality of simple polygons without changing the information for modeling the interior boundary of the complex polygon;
• combining the interior and the exterior boundaries of the simplified polygon by a straight line connecting them to obtain simple polygons without the interior boundary;
• and
• dividing the simple polygon into a plurality of triangles by using the method for simple polygon division to acquire information for modeling.