Automated Generation and Layout Design of Fabrication Drawings for Building Façade Mullions Using BIM

Modern production efficiency of building components is highly relaying on the approaches of generating fabrication drawings, which consist of all the details required to fabricate the components. Differ from construction and... [ view full abstract ]

Modern production efficiency of building components is highly relaying on the approaches of generating fabrication drawings, which consist of all the details required to fabricate the components. Differ from construction and architectural drawings, fabrication drawings often contain more than one drawing views with complex geometries, and the number of fabrication drawings is normally very huge, thereby leading to tedious and inaccurate works on layout design, especially scaling and dimensioning of different drawing views. Automatic design of drawing layouts is thus significant for speeding the generation of fabrication drawings. For building components having similar structure such as façade mullions with a variety of holes or circle notches, the decision making regarding to the generation of proper section views is one of the major tasks which consumes a lot of labor. This paper proposes a BIM-based framework for automated generation and layout design of fabrication drawing layouts for building façade mullions. Algorithms such as detection of holes are developed and applied to obtain necessary section views for the fabricate purpose, based on which the simulation of scaling factors for drawing views is conducted to obtain the primary values. For any drawing view, a suitable bounding box is generated to fully represent the space it occupied with a proper aspect ratio determined by the pre-defined canvas, the final scaling factor is obtained by rounding off the primary factor referring to the best fitting of the view. According to the scaling factor of the side view,  the top view breaking and rescaling is applied. In addition, primary dimensions of the views are also generated by either importing the 3D dimensions or using suitable algorithms. Proper fabrication drawing layouts for façade mullions are thus generated with a consistent format. For a better understanding and verification of the developed framework, an example containing the 3D model of a mullion and its corresponding generated fabrication drawings is given.