METHODOLOGY FOR HOT AIR BALLOON ENVELOPE MANUFACTURING BY REVERSE ENGINEERING AND FLATTENING TECHNIQUES

This paper presents the application of reverse engineering and flattening techniques to the design and manufacturing of the envelope of hot air balloons used for advertising. Aim of the herein described methodology is to obtain a shape of the hot air balloon as close as possible to the object to reproduce: this is accomplished acquiring with Reverse Engineering techniques the surface of the object and then applying advanced flattening algorithms. The manufacturing of the balloon is made sewing plain strips of fabric, which once assembled form a 3D shape. The final result is a 3D shape pressured and lift by the hot air confined inside the envelope. A CAD applet and a flattening algorithms have been developed since no commercial software is available for this application. The validation of the methodology has been done applying it to the realization of a small model of an hot air balloon representing a coffee pot. The paper describes all the phases of the methodology: from the acquisition of the shape to the realization of the envelope. The final result obtained is quite good and confirms the effectiveness of the flattening algorithms developed and of the methodology in general.