I don't think CC likes me

I am trying to do a simple Boolean function.
Each time I try to create a rounded corner either the circle or the square just deletes itself?
I try selecting the circle first or the corner and it keeps doing the same thing?
I have tried this on all the function buttons with the same thing happening?

You can’t really make a rounded corner that way:

  • if you use Union, you end up with the square since it contains the circle already
  • if you use Intersection, you end up with the circle since this is the only common area to the circle and the square
  • if you use Difference, well you end up with a circle-shape hole in a square.

For this specific case, shouldn’t you rather use the Fillet option in the Rectangle ? (unless what you display is not a rectangle, but an arbitrary shape with a 90° corner somewhere…)

@WillAdams should be able to do his magic to do what you want using multiple boolean ops and steps, but it may be more involved than you expect.

so fillets are great for this…
but the indirect way is to subtract the circle from the box. that leaves the top left “inverted” thing,
You then subtract THAT from your box… and you have the rounded corner


Booleans seem like they are a tool with which you can accomplish just about anything. It might not be an easy tool and the path might not be obvious…but it can get you there. But I sure wish there was a ‘trim’ tool in CC where you could delete a segment of a vector but cutting it with another.

Tutorial on this at:

hang on for a step-by-step for your specific case.


For this specific case, you have to turn things around a bit:

First, draw in a square to notch the corner out of:

Select the square and shift click on the circle making it the key object:

Boolean subtract the circle from the square:

delete the circle, select the rectangle, then shift-click on the notched square making it the key object:

Boolean subtract:

delete the notched square:

Lots of other ways to do this.


All of that for a fillet? Out of curiosity I downloaded CC once, but I quickly realized how happy I was with Solidworks.

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this is doing a fillet the hard way … the easy way is to draw the box and select that you want a fillet :wink:


Correct, see:

As noted, there are lots of other ways to do this:

First, just choose Fillet:

Or, use Node Editing (which is the closest thing to Trim):

right-click on the path:


Select the modified rectangle and the circle:

Boolean Union:


Oops, I new there was an easy way to do it. For the life of me, I couldn’t remember.
Simple, make a square and where it says Square use the drop down and select Fillet. Radius can be adjusted from there. DUUUUH!
I have done this before.
My sincerest apologies!
Eric :frowning_face_with_open_mouth:


Just adding this to the list of EASY methods…it’s actually one that @WillAdams taught the group a few months ago - I’m surprised he didn’t suggest it here:

Start with your square and do an INSIDE offset of whatever distance sets your radius

Then, immediately do an OUTSIDE radius with the same settings, using the inside object (which is still selected)

VOILA! Remove the extraneous objects and you’re left with the filleted rectangle. The beauty of this method is that it will work with any shape and is just a couple of keystrokes. All hail, @WillAdams !


I didn’t mention that one because the OP specifically wanted Booleans, and my assumption was that they were trying to round off a single corner.

Yeah…but that method is just SO sweet. Literally four keystrokes and no brains. Perfect.


@WillAdams OK…then here is a REALLY EASY way to do it to one corner with booleans:
Start with your shape:

Draw another rectangle with the fillet that you want (or use Will’s method to create one) and make sure that the corner you want to round is lined up and that all the other corners of the new filleted shape are OUTSIDE of your original box (you might need to resize and reposition the shape if you don’t create it with the fillets and in the right place):

Then add your original box to the selection:
Click Boolean Intersection


And then if you only want one corner with a fillet, square the other corners with a Boolean add!

Of course…but if you want to ease the corners of something other than a rectangle, knowing these other methods will definitely come in handy!

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Thanks for posting these methods. I am a novice at this CNC stuff and do it strictly as a hobby. I have watched many videos and never encountered ‘auto filleting’. I have spent a few hours trying to round corners on different shapes using Boolean operators with - to put it politely - mixed results.


@72begin My pleasure. We’re all here to help each other out.

The trial and error method of learning software can be a bit tough. Carbide seems to be putting more effort into more structured video tutorials lately - so that’s great. It takes a fiscal commitment to create good written education and documentation for a software product…and some other products do a great job of it and can be used as an example. The Carbide team is putting their money into other aspects of the product and doing a great job of producing very useful products and accessories. I do hope they continue to build their education wherever possible.

So, when in doubt, there’s always @WillAdams ! :slight_smile: