The clearance plane is cylinder and defined along the axis of rotation wherein all transfer motions between a retract and engage motion takes place. Typically you would define this plane at a certain safety distance above the part geometry. This is done to prevent the tool from touching the part being machined during transfer motions since these motions usually use a very fast or rapid feed rate.

Automatic

The system determines the clearance height based on the part and stock geometry.

Part Max R + Dist

Uses Part maximum plus the specified radius (R) distance for clearance height.

Stock Max R + Dist

Uses Stock maximum plus the specified radius (R) distance for clearance height. If stock geometry does not exist, it would use the maximum height of the part geometry.  

Absolute R Value

Uses the specified radius (R) distance for clearance height.

Ignore Wireframe Geometry in Bounds Computation  

Check this box to ignore all wireframe geometry when calculating the Clearance Plane definition.  When checked, the Automatic and Part Max options for defining the Clearance will be calculated from actual surface geometry.

This section allows you to control the tool's motions when it needs transfer to another region to begin cutting.