Making sky lanterns from polygonal meshes

National Natural Science Foundation of China [61202142, 61100032]; Funds of the Ministry of Education of China and China Mobile [MCM20122081]; National Key Technology R&D Program Foundation of China [2013BAH44F00]; Fundamental Research Funds for the Central Universities [2010121070, 2010121072, 2013121030]; Singapore NRF Interactive Digital Media RD Program [NRF2008IDM-IDM004-006]; Central South University [2012QNZT058]; Ministry of Education of China [20120162120019]Releasing sky lanterns is a popular way of celebrating festivals and ceremonies in the Asian countries. This paper presents a computer-aided approach to help novice users to design flyable sky lantern with desired shape. Given a closed up-right 3D model with a user-specified cutting on the bottom, our system optimizes the shape by regularizing the boundary, smoothing the geometry and improving the volume-to-area ratio to make it feasible for flying. The optimized shape is then approximated by a set of developable patches. Next, through a physical analysis step that tests the flying condition and determines the optimal size, the approximated shape is flattened into 2D patches, which can be printed out and glued together to form the airbag. Finally, the user can attach the airbag to a bamboo frame and assemble the fuel cell. We successfully apply our prototype system to design and construct real sky lanterns. (C) 2014 Elsevier Ltd. All rights reserved