Bubble fillet for 2D toolpaths?

Is there a way to achieve a “bubble fillet” on a 2D corner? AlphaCAM has a feature called bubble fillet which eliminates the need for drilling out dogbones – it rounds off corners in such a way that corners are eliminated without requiring a drill pass. Seems like a simple enough feature which would make a HUGE difference for CNC toolpath workflows.

Hi Michael - I made a script thing that makes dogbones andf t-bones - can you post and exemple file, I made this for a particualr situation, I might need to tweak it for yours.


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Here’s a sample of what I’m trying to do. Basically a continuous toolpath that uses a 3/8" (0.375") bit.

Thank you!

bubble_fillet.3dm (124.0 KB)

Hi Michael - my tool takes a closed curve as input and dogbones all interior (or exterior if the path is a hole in the sheet) corners. You don’t get to choose each corner, in other words, it does them all.

would that help?



Hell yeah! Thank you so much!

Hi Michael - see how this works - it is soemwhat tested in real life, not a lot.
Save the rhp file and in Windows Explorer, Unblock the file, then drag and drop it onto Rhino.

the commands are

Input is a closed planar curve - you tell the tool whether the curve is hole or not, so it knows which corners to hit, , and set the radius.

The DepthFactor is a slight overshoot, .05 radius, I think, by default, to make sure there is clearance.

Bones.rhp (35 KB)


Wow, this is an absolute game changer! I can’t thank you enough!