Graph theory-based approach for automatic recognition of CAD data

CAD architectural plans basically contain original geometrical information of graphical primitives. However, in many applications, such as building's 3D reconstruction, auto-detecting errors of design, original CAD data are very hard to be directly utilized. It is always a time-consuming and exhaustive task to extract useful information like the coordinates of a line from CAD files. To make this task performed in more efficient way, a way to develop an automatic method to extract spatial information from architectural plans produced in the form of computer-drawn CAD drawings is proposed in this article. The aim of the proposed method is to provide automatic transformation of architectural drawings into the spatial and topological information of the enclosure in a building. To auto-understand the ‘meaning’ of the graphic elements in the drawings such as walls, doors and rooms, the approach employs algorithms in graph theory, which can identify every functional component in the enclosure and establish their connectivity relationships. The method has been implemented by using object-oriented C++ language and is found to be able to produce satisfying results.