What does G-code control in 3D printing?

G-code is a language that serves as the standard for controlling CNC (computer numerical control) machines, which includes 3D printers. It provides a set of instructions that governs the movements and operations of the printer. This encompasses details such as the path that the printer's nozzle will take, the speed of movement, and the temperatures required for the extruder and heated bed. By translating the design created in CAD software into a form the printer can understand, G-code facilitates precise execution of the printing process.

The other options do not accurately describe the function of G-code. The aesthetic design of printed objects is determined by the design software used and the parameters set by the user but is not directly controlled by G-code. The software interface for the 3D printer helps users operate the printer, but it does not directly involve G-code, which is generated by slicing software that translates 3D designs into the G-code commands. Lastly, the materials used for printing are essential for the process but are not dictated by G-code itself; rather, they are selected based on the capabilities of the printer and the requirements of the intended print.