From FreeCAD Documentation
- Select sketcher elements in task panel or in 3D view.
- There are several ways to invoke the command:
- Press the Rectangular array button.
- Select the Sketch → Sketcher tools → Rectangular array option from the menu.
- Specify the options for the array in the dialog that opens.
- Press the OK button.
- Move the mouse in the 3D view towards the desired reference point.
By keeping Ctrl pressed, the angle to the reference point can be fixed in steps of 5°. introduced in version 0.20
- Left-click in the 3D view to create the array.
- To set the distances between the array elements, edit the dimensional constraints of the array.