WISRD Research & Engineering Journal

3.2 Software To 3D print objects, two types of software are required: CAD and a slicer. We used Onshape and Ultimaker Cura respectively. Onshape (web-based Computer Assisted Design (CAD) software) was used to design the substrates because it offers free student accounts, is easy to use, and files can be shared among collaborators. Ultimaker Cura was already in use in WISRD, as it is used with other 3D printers. Once the design was created in CAD, it was exported as an .stl (standard tessellation language) file. This file format is opened by slicing software, in this case Ultimaker Cura, which reads the .stl file and allows the user to change various aspects of the print, such as order, path, and infill. It then converts the .stl file to G-code. G-code is a programming language used by computer- controlled manufacturing machines called Computer Numerical Control (CNC) machines. The file itself contains lines of command that give these machines, such as our 3D printer, precise directions on where to move its parts in the creation of the print. The G-code file essentially provides instructions for the printer using these commands. The file tells the printer in which direction to move and when, to accurately and correctly build a sliced object. This process is shown in Figure 6.

Figure 6. Diagram showing files used in creation of a 3D-printed object, from designing in CAD to final printed object. (Roy, 2022) 3.3 Evolution of Designs and Prints Our earliest designs were created by Luca G. His conception, as shown as sketches in Figure 7, was a two-piece system: (1) a base with legs and a hollow square with bracing inside that would support a surface, and (2) a surface with grooves in which the coral would grow.

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