Neural networks in the re-engineering process based on construction drawings

In this paper an approach is presented to digitize a drawing, to build up geometric and topologic models, to recognise construction parts and to interpret dimension lines and inscriptions. All recognized parts are transformed into a three-dimensional geometric model which provides all necessary geometric information for a product model. The recognition process of construction parts is based on a line search and topological analysis, which are not suitable for the recognition of drawing inscriptions and hand writings. Therefore, the information of dimension inscriptions has to be neglected in former case studies. Because dimension inscriptions deliver significant information about the dimensions of construction parts, a neural Kohonen network is implemented and adapted in order to recognise inscription text. Finally the gained information about dimensions is related to significant details of construction parts. C o n st ru ct io n I n fo rm at ic s D ig it al L ib ra ry h tt p :/ /i tc .s ci x. n et Figure 1. Scanned ground floor plan of the barrack building All algorithms and methods are implemented with the Java programming language. A case study of an existing building demonstrates the usability and efficiency on the outlined approach. This case study concerns an old barrack build in the beginning of the last century and used nowadays as offices of the University of Hannover. A ground floor plan of the first storey of this building is shown in Figure 1. The identified inscriptions, dimension lines and in particularly the corresponding relationship to construction parts are illustrated in detail. For a demonstrative explanation a detail (Figure 2) of the ground floor plan is used. Finally the whole ground floor plan is shown in Figure 14 as result of the identification process after the integration into the IFCproduct-model. Product modeling is one of the key issues of the DFG priority program 1103 (DFG 2005) concerning network based co-operative planning processes in structural engineering. Consequently, the actual research work has been considered in strong correlation to this priority program with a special focus to the re-engineering process of existing buildings.