Legolization: Optimizing LEGO Designs
Chun-Kai Huang1
Yu-Huan Chung1*
Sei Imai3*
Tomoyuki Nishita4,5
1 National Taiwan University
2 Columbia University
3 The University of Tokyo
4 UEI Research
5 Hiroshima Shudo University
ACM Transactions on Graphics (Proceedings of SIGGRAPH Asia 2015)
Our method transforms an input 3D model (a) into a physically stable LEGO model (c) that can be realized in the real world (d).

Abstract
Building LEGO sculptures requires accounting for the target object’s shape, colors, and stability. In particular, finding a good layout of LEGO bricks that prevents the sculpture from collapsing (due to its own weight) is usually challenging, and it becomes increasingly difficult as the target object becomes larger or more complex. We devise a force-based analysis for estimating physical stability of a given sculpture. Unlike previous techniques for Legolization, which typically use heuristic-based metrics for stability estimation, our force-based metric gives 1) an ordering in the strength so that we know which structure is more stable, and 2) a threshold for stability so that we know which one is stable enough. In addition, our stability analysis tells us the weak portion of the sculpture. Building atop our stability analysis, we present a layout refinement algorithm that iteratively improves the structure around the weak portion, allowing for automatic generation of a LEGO brick layout from a given 3D model, accounting for color information, required workload (in terms of the number of bricks) and physical stability. We demonstrate the success of our method with real LEGO sculptures built up from a wide variety of 3D models, and compare against previous methods.

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@article{  Luo:2015:LOL,
   author = {Luo, Sheng-Jie and Yue, Yonghao and Huang, Chun-Kai and Chung, Yu-Huan and Imai, Sei and Nishita, Tomoyuki and Chen, Bing-Yu},
   title = {Legolization: Optimizing LEGO Designs},
   journal = {ACM Transactions on Graphics (Proc. SIGGRAPH Asia 2015)},
   volume = {34},
   number = {6},
   pages = {222:1--222:12},
   articleno = {222},
   numpages = {12},
   year = {2015},
   publisher = {ACM},
}

Acknowledgements

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