Circle or donut divided into sectors - 1 method works, another doesn't

[cadobir]

A poster on the AD/AP group on Facebook asked:

 

"I need to create a 'doughnut' shape (so a larger circle with a smaller circle punched out the middle) that is divided into 12 sectors"

 

​I offered him this solution, which seems like it should work - but it doesn't: (See screenshot: Method 1.png)

 

"Make a circle with the ellipse tool. There is an option to "convert to donut"; choose that. Then make a 12-point star to the same diameter, with inner diameter set to zero. Align them and select both, then choose divide."

 

Then I offered him this solution, which does work: (See screenshot: Method 2.png)

 

"Start with the ellipse tool and draw a circle. Then choose the option to "Convert to Pie", Accept the Start Angle to 90 degrees. For 12 equal segments, you'll want them to be 30 degrees each. AD reads the circle counter-clockwise, so set the End Angle to 120 degrees. Set the Hole Radius to something suitable, like 40 degrees, for example. You'll now have one-twelfth of a circle with a hole in the middle. Duplicate the layer. Make the Rotation Center visible and place it where the center of the circle should be. The new layer contains a duplicate of your segment; with the Rotation Center aligned, rotate the new segment 30 degrees. Then just duplicate that layer 10 more times."

 

My question is: Why doesn't the first method work? It doesn't work even if I convert the objects to curves. I can't understand why it wouldn't. 

[JimmyJack]

If you make the inner and outer radii 0 then you will essentially just have lines. And trying to boolean with lines isn't supported yet. (you may get some result, but most likely a weird one)

Technically, you will have two lines right on top of each other for each arm.....still, boolean can't handle it. There is no real volume for boolean to work. That's my theory anyway.

 

 

The star method will work though if you type in a super small value.

I used .0001. (When I hit return the value in the window said zero but there really is some thickness there .... try it).

 

So I put in a value of .0001% for both inner and outer. Used boolean subtract, and then boolean divide.

The one caveat is that there will be a teeny tiny separation between sections. (...that can be compensated for with a stroke.)

 

Edit 1: Oh yeah.... I think it's also important to have the star points end beyond the outer rim of the donut. Just to make sure the cut is complete. If you snap to the exact donut size, you might get some ugly artifacts.

 

Edit 2: Oh yeah again.... there's also a Donut tool is the shapes list, so you don't have to make your own. :)

[cadobir]

Thanks, JimmyJack, you are absolutely right. I tried what you suggested and it worked very well. Thank you so much!