Filet corners on shapes other than square

My niece will have her first birthday this weekend, and I want to make a simple shape sorter/puzzle for her. The puzzle has a triangle, circle, and square.

I’m able to add a radius on the triangle pocket simply using the radius of the bit, because it’s an inside cut. However, I’m not sure how to add a matching radius for a contour operation that would create the actual triangle puzzle piece.

12-18-Three-Shape-Puzzle.c2d (17.6 KB)

I would just make the triangle puzzle piece a hair larger than the pocket hole (By the width of the bit) then do an inside cut and it should add a radius to the corners…

Same thing with the square

Add Circle to Desired Diameter
Circle added to match Bit diameter
Boolean Subtraction with Circle Dotted
With Circle dotted select boolean subtraction.

Resize cut geometry to be slightly larger than corner. Must overlap for Boolean to work correctly. And select the inside corner to have the dotted line. (select last) Then select Boolean Subtraction again.

Corner is now radiused and can be repeated for the rest.


Thank you, @mjmike6988

I was attempting to use this method, but kept coming up short. I probably had the wrong shape selected.

If you get undesired outcome from boolean, CNTRL Z usually reverses the dotted lines between geometry. I do this alot when in a hurry and not paying attention.

My work above could be better but just trying to provide concept.

@robgrz The corner options currently present for the Rectangle tool would be a welcomed addition to the Polyline tool. Then this operation could have been completed without any real thought and create improved workflow.

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An easier solution is to inset by the radius, then offset to the outside.


I totally forgot about the radius when Offsetting in CC, forgive me I bounce around through so many programs. From his post I was just thinking of him trying to use boolean operations.

This would indeed be quick to do in CC, But would still like the corner options for the Polyline (wink wink)

As Will mentioned, Offsetting this triangle inside .125 and then offsetting that .125 to the outside will result in .125" radiused corners allowing clearance for a .25" Bit


Another option, could be to create the triangle, then create an “Offset” to the outside of the triangle, which will create curved corners, then when you pocket cut the shape into the base, and no offset or inside offset contour cut the block, there should be enough gap where the block fits into the base. (Disclaimer: I have not actually done this, but it seems logical).

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