To prevent unnecessary air movement, with ecam is possible trim toolpaths in several way.
First go to Trim Toolpath / Avoid Region screen. Click in highlighted link.
Now you can choose to trim the toolpath outside the stock profile.
Simply check Trim Toolpath outside stock option.
After that you can see the toolpath is already trimmed.
This option is similar to the Trim Outside stock, but the trim geometry is defined by user selection.
Is possible also avoid some defined geometry.
When you have to clear a large area, probably you are going to use a end-mill with most larger diameter to speed up the machining time.
The downside is a lot of material remains in corners, so you need to remove it.
Here comes in handy the remachining operation, it goes to remove the uncutted material from previous operation.
Rest machining with smaller endmill:
Previous operation with larger endmill: