Research On Recognition Of Building Units Based On DXF

With the rapid development of technology, people are increasingly seeking visual enjoyment. The traditional two-dimensional architectural drawings have been unable to meet people's need, but the current architectural drawings still use relevant data of two-dimensional information to build 3D model. However,3D model can't directly be built just through two-dimensional architectural drawings. It requires the use of certain computer-related technology to read and identify two-dimensional graphics and then automatically generates 3D model. Building 3D virtual models have been widely used in film, machinery, medical and other fields. Nowadays, people pay more attentions to Automatic 3D reconstruction technology.The key of 3D reconstruction is the job of building units recognition. We put forward a solution of building units automatic recognition. Firstly, extract information of DXF file ENTITIES, including end point coordinates, circle coordinates,arc coordinates, layer and other information. Then select wall lines and window lines from the identified lines according to the layer information. According to the composition of the wall, the wall lines must be paired, parallel to each other, the distance between the wall lines within the threshold range, public projection in the X-axisor or Y-axis and so on. Then identify wall. According to the composition of the window, the window lines must be three or four, parallel to each other, the distance between the window lines should be close and so on. Then identify window. Finally, divide the wall and the window into left, right,top, and bottom four parts. Select the most left, right, top, and bottom lines. Then based on these four lines, according to the characteristics of the same slope, the distance between adjacent points within the threshold range, and having maximum or minimum of intercept, identify the left, right, top, and bottom out-wall. Add the same side and adjacent out-wall horizontal or vertical.Then, finish the recognition of the out-wall.This article in VC++6.0 programming plat accomplish the extraction of DXF file information, the recognition of wall, window, and out-wall. The results through MATLAB simulation validate that the solution of building units automatic recognition we put forward is available.