This parameter is the Z value for the top of the part
2 Axis operations
The Geometry parameter on the Cut Control tab controls this value.

If Geometry is set to Top,
then the ZRange Filter Top Z value = the Z coordinate of the part.
If Geometry is set to Bottom,
then the ZRange Filter Top Z value = the Z coordinate of the part + the Amount To Remove In Z.
If Geometry is set Top Z,
then the ZRange Filter Top Z value = the entry for the Top Z option.
If Geometry is set to Bottom Z,
then the ZRange Filter Top Z value = the Bottom Z entry + the Amount To Remove In Z.
3 Axis operations
The Top Z value is the highest Z value on the part.