Snapping
When generating parallel or fanned holes, the following snapping operations can be applied:
Snap to an existing pivot point
Hold down the CTRL key as you digitise a point which is in close proximity to the pivot point you want to snap to.
Snap to the nearest hole
You can also hold down the CTRL key to snap to the nearest hole when using the mouse to define an area (rectangle or arc) in which parallel or fanned holes will be created.
In this way, additional holes can be added equidistant to, or at a specified distance from, existing holes.