While on manual machining, this video covers the considerations when doing this quite well:
The new 843 beta includes a “Cutout” toolpath:
which can be useful for that, or, leave a roughing clearance and take a finishing pass with a suitable tool and toolpath.
@WillAdams If one wanted to leave an onion skin pass on the Breakthrough, how would you enter a number in that field? T+(onion skin thickness)?
Enter a negative number — positive ones will overcut, negative undercut.
Is there any documentation regarding the new cutout toolpath? Sounds interesting so I’d like to know what it’s for and how to use it…
Build 843
New
Added a new “Cutout toolpath” that automatically determines if you need multiple offsets to avoid deep slotting. Cutout toolpaths will not load in prior versions.
I showed using it in:
So it seems like it creates a pocket behind the scenes? Is it smart on how it generates the pathing? eg plow the groove on the outside first to avoid chattering against the selected vector?
It’s all new code, so it’s not really a pocket. It goes to some length to handle edge cases and keep the paths together (like a C where the outer pass turns into an island and an outline), but don’t recall any hard requirement to maintain a particular order, because there were LOTS of edge cases where absolute requirements broke down. Taking a step back, the paths are never meant to be deep enough to be a problem compared to truly “plunging and plowing”.
As was mentioned in another thread, tabs seem to be missing on the new cutout toolpath. I just ran a test file and found the tabs are not there even though I checked the “Use Tabs” box. In the attached file I made two toolpaths. The contour cuts as expected leaving the tabs but not the cutout toolpath.
Cutout Test.c2d (60 KB)
I also just noticed the simulation of the wide cutout runs 11 more times around the circle after the breakthrough so I changed the breakthrough to “t” and it ran 13 times more.
Am I using the wrong settings?
The value for Breakthrough is relative to the Bottom of the stock.If you specify a value greater there than the thickness of the tabs then the tabs will appear below the stock.
I reset the value to 0 and the tabs show up but only on the inside of the cut. Would it not make more sense to have them extend across the width of the “wide” cut?
We can duplicate this; we’ll get it taken care of.
@robgrz I also found out yesterday that even though my tab size was set to 5mm x 3mm it was cut at the default 25mm x 6.35mm
@robgrz Sorry…one more thing I found was the cutout is cutting outside the selected vector leaving an edge around it.
Jeff, that appears normal if you V-carved inside the vector & cutout the outside.
You would need to offset the vector to make them overlap. Or contour the vector with no offset to remove the taper from the Vbit.
You can’t rename cutout operations.
You also can’t do an inside cutout.
A Cutout is essentially a contour with extra passes.
@Tod1d & @WillAdams Yeah 
This example is the plug side of my feather inlay so maybe I just need to add a contour toolpath to the perimeter to remove the edge or if it’s thin enough I’d just snap it off and rough sand it smooth so it doesn’t interfere with the inlay depth when clamping
Adding a contour works and previews as:
