Lego brick approximation of mesh bodies

• Main Author: Bautista, Natasja Gail R.
• Format: text
• Language: English
• Published: Animo Repository 2007
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3522
• Institution: De La Salle University

The Lego company presented the question “Given any 3D body, how can it be built from Lego bricks?” at the SCAI’01 Conference. To address this, we propose a solution to the automatic approximation of a 3D mesh body by its LEGO brick representation. The algorithm is defined by two parts, namely: (1) voxelization; and (2) Lego construction. For voxelization, an input 3D mesh is transformed into a 3D grid structure to mimic the blockiness produced by Lego bricks. Once voxelized, the Lego construction algorithm will read one voxel layer at a time and produce two levels of Lego bricks for each layer. The first Lego layer is the base layer, which is composed of Lego bricks patterned after the shape of the voxel layer’s surface. The second Lego layer is the connecting layer, where values are assigned to the edges of the Lego bricks in the base layer depending on the number of bricks adjacent to it. These values will determine placement of bricks in the connecting layer. The integration of all Lego brick layers will then produce the final result. The study was able to approximate 3D mesh bodies into their Lego brick format using dynamic programming and heuristics. Results produced using mid-to-high levels of detail resulted to connected Lego models, although special cases arise such as disconnected diagonal bricks. Increasing the level of detail approximates the shape of the input mesh more accurately but uses up more bricks when compared with results at low levels of detail. The automatic construction cuts down the time it would take to manually conceptualize models from scratch or through Lego CAD software. The resulting Lego models can also be converted into the standard .LDR format used by the Lego community