In 3D modeling, splitting an object down the middle is a technique used to create two symmetrical halves. This can be useful for creating objects that are symmetrical or for creating objects that can be easily mirrored.
To split an object down the middle using 3D Builder, select the object and then click the “Edit” menu. In the “Edit” menu, select the “Split” option. A dialog box will appear, prompting you to select the axis along which you want to split the object. Select the “X-Axis” or “Y-Axis” option, and then click the “OK” button.