In this study, we propose an Algorithms-Aided Design (AAD) approach to shift the center of gravity of 3D printed artifacts to a predefined location by creating a heterogeneous internal structure utilizing the same type of material. When the conventional design and fabrication pipeline of 3D printers and additive manufacturing machinery is employed, information about the interior of the artifacts is lost during the conversion of the design files to the STL file format. This de facto file standard only stores the boundary information of the objects. Even though the designed artifact has heterogeneous interior in the Computer Aided Design (CAD) software, after the conversion it becomes a homogeneous solid. Our method does not require an STL file, since we are using a query-based approach in which the built-in algorithm communicates with CAD software to acquire the necessary information about the design for manufacturing. According to the proposed pipeline, the designed artifact in CAD software is first decomposed into voxels having predefined sizes with AAD add-on software. Then, the desired center of gravity and the amount of extra material available are entered by the user and this additional material is distributed to the voxels by our developed algorithm so that the center of gravity of the final artifact is at the predefined location. At the end of the design process, filling percentages of some voxels is altered which made the structure internally heterogeneous. Then the final structure is directly sliced and the trajectories are converted to G-codes. Using the generated file, artifacts are printed on a desktop FFF printer. With the developed algorithm, we can modify the coordinates of the center of gravity of any shape by adjusting their interior structures and fabricate them on FFF printers. (C) 2018 The Authors. Published by Elsevier B.V.
