Clearance area is the area specified by the user where the tool can travel in the air without hitting the work piece. This can be a plane at a given height or cylinder or sphere.
Here the feed rate of the tool is rapid speed. From the clearance area the tool moves to rapid distance and during moving the head turns to its final orientation. So that at rapid distance the tool has the right orientation for the first cut.
Depending on the drive surface or your machining strategy you can also set the clearance area type.
The available options are: