33 Replies Latest reply on Mar 5, 2012 6:52 AM by Jabbo126

# How to divide a circle intio three equal segments

I would very much appreciate any advice on the best way to divide a circle into three equal segments, such as the one that can be seen here: http://www.visualfractions.com/EnterCircle.html. I need to divide the circle with Object > Path > Divide objects below.

Thanks!
• ###### 1. Re: How to divide a circle intio three equal segments
Daniel,

You can:

1. Create a straight path at least as long as the radius starting at 0,0;
2. Select (one of) the Reference Point(s) in the Transform Palette yielding 0,0;
3. Ctrl+C and Ctrl+F and select 120 degrees, still in the Tranform Palette;
4. Repeat 2 and 3;
5. Create the circle and move the centre to 0,0;
6. Select all, Pathfinder>Divide, and Control+Shift+G to Ungroup.

This is the Divide a Circle into Thirdendeals Thread.
• ###### 2. Re: How to divide a circle intio three equal segments
Just an alternate method for Jacob's steps 2-4: use Effect | Distort & Transform | Transform. That dialog enables you to select the anchor and the two copies needed in one swell foop.

You do need to expand appearance before proceeding to step 5.
• ###### 3. Re: How to divide a circle intio three equal segments
Jacob,

Thank you very much for your answer, but I'm afraid I can't follow it. Could you be a bit more specific? Let's say I want to create a circle with a radius of 30 mm.

Ok... so I...

1. Create a straight path (using the pen tool?) of 30 mm starting at 0,0 (from 0,0 to 0,30).
2. Select the 0,0 (with the direct selection tool?) extreme of the straight path (only one of the two extremes of the line is 0,0)
3. Then I'm lost

Daniel
• ###### 4. Re: How to divide a circle intio three equal segments
Harron and Jacob,

I'm afraid you're both asuming I have a good command of Illustrator. But that's not the case (I come from the PhotoShop realm, and am not very used to working with vectors). And I just need to make a circle divided into three identical segments, each of them with a different color, such as you would see in a pie chart with 33,33% for each of the three segments.

I would very much appreciate a little more detailed step by step explanation from any of you.

Thanks a lot!

Daniel
• ###### 5. Re: How to divide a circle intio three equal segments

I switched to points to get the GIF nice (85.04 pt corresponds to 30 mm).
• ###### 6. Re: How to divide a circle intio three equal segments
I cannot believe it. I followed Jacob's instructions over and over until I finally achieved it (had to figure out a couple of things that were not that clear to me at the beginning).

Thanks a lot to both of you!!!

BTW... What does Ctrl*F do exactly?

Daniel
• ###### 8. Re: How to divide a circle intio three equal segments
Daniel:

Another simpler method-

Select the Polar Grid Tool (mouse down on the line tool and pick the right most button.

Click the artboard and enter equal W and H, 0 Concentric Dividers, 3 radial dividers, OK, and then either--

A- Use the Live Paint Tool to fill the segments

B- Use Pathfinder Palette Divide to break the circle up into separate pieces.

steve
• ###### 9. Re: How to divide a circle intio three equal segments
Much better!
• ###### 10. Re: How to divide a circle intio three equal segments
I May have done something wrong, but it looks like divide will not work unless you ungroup more than once.
• ###### 11. Re: How to divide a circle intio three equal segments
It will in 10, Silk.

I was in a hurry with the screenshot, last night before closing down; I would have moved the Layers Palette into the frame to show that there were an unselected path beneath the selected one, but the Charcter Palette slipped in.

Nice Harron and Steve, and you are welcome Daniel.

But as I said: this is the is the Divide a Circle into Thirdendeals Thread. There must be more ways.
• ###### 12. Re: How to divide a circle intio three equal segments
> There must be more ways.

Personally, I'd use the Polar Grid tool. Clickdrag, but don't mouseup. Press and hold the down arrow key until you have only one circle. Tap the left arrow key until you have only three radii. Press and hold shift to constrain the circular proportion, then mouseup.

But then I would be annoyed that the three pie slices have four points each. So...how do you make three 120 degree pie slices with only three tidy points each?

1. Polygon Tool: Mousedown at some pre-existing snap location. It could be the intersection of two guides, an anchorpoint of a path, etc. Drag, but don't mouse up. Tap the down arrow keys until the polygon has only three sides (an equilateral triangle).

2. WhitePointer: Select two of the triangle's anchorPoints. Click the Convert To Smooth button. Select the other anchorPoint. Click the Convert To Smoot button. (Why two operations? Because in Illustrator's lame Control Panel, the Convert / Cut Selected Points buttons disappear if all the points of a path are selected--more evidence that Illustrator doesn't know the difference between a path being selected as an object and merely having all its points selected.)

3. Select>Path>DirectionHandles.

4. ScaleTool: AltClick the snap-to location that was used in step 1. In the resulting dialog, enter 128.4%.

5. Ctrl-X (Cut to clipboard). Delete. Paste In Front.

6. White Pointer: ShiftClick one of the three pasted paths to deselect it. Delete (the other two are deleted.)

7. Pen Tool: Click one of the endpoints. Click the snap-to location. Click the other endpoint.

8. White Pointer: AltClick the path to select all of it. Scale Tool: AltClick the snap-to location. In the resulting dialog, enter 120 degrees, click Copy. Ctrl-D (Transform Again).

JET
• ###### 13. Re: How to divide a circle intio three equal segments
Jet,

Fantastic. (That would be Rotate Tool in step 8?)
• ###### 14. Re: How to divide a circle intio three equal segments
Mass execution:

http://illustrator.hilfdirselbst.ch/Sonstiges/Sample_AI_Files/mass_execution_001.zip (AI 10 format, ca. 70 kb)
• ###### 15. Re: How to divide a circle intio three equal segments
> That would be Rotate Tool in step 8?

Oops. Yep.

JET
• ###### 16. Re: How to divide a circle intio three equal segments
Here's an idea...
2. Activate your star tool. Draw a 3 point star.
3. Place your 3 point star exactly inside your circle, where the points touch the circle.
4. Get out your scissors tool. Clip each segment at the point.
5. Delete the star. Voila! 3 perfect segments.
• ###### 17. Re: How to divide a circle intio three equal segments

There must be other ways.
• ###### 18. Re: How to divide a circle intio three equal segments
OK Jacob:

With the Ellipse tool make a circle (e.g. W- 50pt, H- 50 pt).

With the Polygon Tool make a larger 6 sided polygon (e.g. radius 50pt).

With View> Smart Guides on (Ctrl + u) and the polygon selected, use the Direct Select Tool (white arrow) to click drag the polygon by one of its anchors to the center of the circle. Smart Guides will say center when you are on.

Select both the circle and the polygon and alt + click Intersect shape areas (top row, three from left) in the Pathfinder Palette. Now you have one piece.

Select the piece, select the Rotate Tool and alt + click the center anchor point. Enter 120 deg and click copy. Repeat this by Ctrl + D to get the third piece.

steve
• ###### 19. Re: How to divide a circle intio three equal segments
By the way...

I'm creating some simple icons to distinguish different type of sites from a client on the map of Europe. These icons, as well as the map of Europe, will be used in Word and Excel.

Now that the icons are ready (in Illustrator), when I convert them to .png or .bmp (to be used in Word and Excel), they look completely pixelated. Is there any other format that I can use to preserve the vector images and the transparencies? Or is there something I should do in Illustrator before converting them into .png or .bmp?

Thanks!

Daniel
• ###### 20. Re: How to divide a circle intio three equal segments
Office productivity programs like Office apps do not natively support vector formats beyond the OS meta formats like WMF and EMF. Office cannot use PDF as spot vector graphics. Nor does it import .ai files and translate their contents into native vector artwork.

Office apps support the now rather dated EPS as an embedded or linked graphic object. But EPS assumes a PostScript printer, and is represented on screen and in non-PostScript print as the low-res raster preview it contains.

So you can try exporting the vector artwork as EMF. Whether the results are satisfactory will depend upon the specific content involved. If you do not find it to be satisfactory, then you are stuck with a raster format, the most versatile of which nowadays is PNG because it includes lossless compression, is not limited to an indexed color depth, and supports alpha channel masking for so-called "transparency".

JET
• ###### 21. Re: How to divide a circle intio three equal segments
RE: Kurt, message #14
File: http://illustrator.hilfdirselbst.ch/Sonstiges/Sample_AI_Files/mass_execution_001.zip

I love your yellow pattern design!
Can you share some of your steps as to how you created that perfect spiral pattern?

Kathryn
• ###### 22. Re: How to divide a circle intio three equal segments
I used the Transform effect, Kathryn.

1) Draw a circle, diameter: 3 mm

2) Effect > Distort and Transform > Transform:

- Reference point: Bottom centre
- Copies: 360
- Scale horizontal: 100,4 %
- Scale vertical: 100,4 %
- Move horizontal: 6 mm
- Rotate: 16°
• ###### 23. Re: How to divide a circle intio three equal segments
Thanks Kurt! You are so smart.

I'll give it a go.

I did try Transform first. I just did not come up with the right numbers.

Kathryn
• ###### 24. Re: How to divide a circle intio three equal segments

My completely blind guess is that if I save every icon mae in Illustrator as an EPS, then open it with PhotoShop and save it with 700 dpi or more, then convert it into high quality .png with transparency I will be able to get an image that preserves the vector look as much as possible.

My guess is that PhotoShop will do a much better job of converting the image into a higher quality .png.

But I cannot figure out the step by step process.

Right now I have around 12 icons in one .ai page. What would you do, step by step, if you followed my theory? I'm tring to find a rational workflow, different from the 12 or 13 steps (some of them useless, I think) I'm now going through. That is, how to convert each individual image to EPS, how to bring them into PS, do I have to save them as .psd or eps in PS after that?, how would you convert them to high quality png after that, what are the Save us parameters I should use in each program (i.e., interlaced/non interlaced, etc,), etc.

Thanks a lot!

Daniel
• ###### 25. Re: How to divide a circle intio three equal segments
From AI you can just select, copy and paste in a new Photoshop document. Here you have two choices...

1/ Create a document beforehand and paste. And the transform to size you want. Crop extraneous materiel and save a PNG with transparency or non-transparency.

2/ Click new and the options will give you size and res and background colour. Paste and save for web or as...

All... very simple and nowhere near 12, 13 steps... probably about 3 or 4 if you plan from before.

Other option is to save each file from AI as an ai or eps file and just open in PS. You're asked for colour mode and size. See all is ok.. Save as...

JJ
• ###### 26. Re: How to divide a circle intio three equal segments
Hi Jay,

I now have an .ai document with 12 icons in it. So I'll tell you what I'm doing and please correct me wherever I'm wrong (probably all over):

1. I select one of the 12 icons, Ctrl+C.

2. Open a new document in PhotoShop, use 1000 ppi (instead of 300 or less). Ctrl+V.

3. Then I just Save as PNG.

Everything fine, except that when saving to PNG I have no control over the size, quality, etc. And the result, seen in Word, looks pixelated.

What am I doing wrong?

Thanks!

Daniel
• ###### 27. Re: How to divide a circle intio three equal segments
Hi Jay,

I took a closer look to the icons in Word and I was wrong: they don't look that bad. In any case, if you think I should correct any part of the aforementioned process, please let me know.

What I don't understand is where does the EPS come into play. And there is some point in which I am asked if I want to use interlace or not. How does this affect the final image?

Thanks again,

Daniel
• ###### 28. Re: How to divide a circle intio three equal segments
To my knowledge Word can import eps files, however on the screen you can only see a thumbnail of the eps file if there is one present. When you print to a postscript printer, Word will pass the eps file on to the printer where it will print at the maximum resolution of the printer.
• ###### 29. Re: How to divide a circle intio three equal segments
Daniel...

1/ Why are you using 1000ppi?
2/ Is the document for network distribution? If it's not going to be printed at high quality all you need 96 ppi. (Windows is 96ppi on an average and Macs are 72ppi.)

What would be best is to save as a .png in close to the actual size you need. Eg... image is to be 4" across on the page. Size the icon fullframe in Photoshop to 4" across @ 96ppi. Save as PNG with transparency (if required. Import into Word. Voila.

There's no need for that eps file. Only time you'd need it is, if you're using an image editor (like PS) that doesn't recognise AI or files from your version of AI.

Silkrooster: Yes, Word can import eps.

Cheers,

JJ
• ###### 30. Re: How to divide a circle intio three equal segments
Is it true that Illustrator doesn't have an object
'circle segment from angle1 to angle2' ?

In PostScript it's fairly simple (save text as *.EPS):

--------------------------------

%%BoundingBox: 0 0 560 560

/mm {2.834646 mul} def
1 mm setlinewidth

100 mm 100 mm translate
/R 90 mm def

1 0 0 setrgbcolor
0 0 moveto
0 0 R 0 120 arc
0 0 lineto
fill

0 1 0 setrgbcolor
0 0 moveto
0 0 R 120 240 arc
0 0 lineto
fill

0 0 1 setrgbcolor
0 0 moveto
0 0 R 240 360 arc
0 0 lineto
fill

0 0 0 setrgbcolor
0 0 moveto
0 0 R 0 120 arc
0 0 lineto
stroke

0 0 moveto
0 0 R 120 240 arc
0 0 lineto
stroke

0 0 moveto
0 0 R 240 360 arc
0 0 lineto
stroke

showpage

------------------------------

Best regards --Gernot Hoffmann
• ###### 31. Re: How to divide a circle intio three equal segments
Back into life.
• ###### 32. Re: How to divide a circle intio three equal segments

Do a pie chart with equal parts, and ungroup the chart.

Done.

• ###### 33. Re: How to divide a circle intio three equal segments

Yes, i want to write this, it's like ... 10 sec solution? :-) But it is really awesom how complicated solutions i find here :-)

edit: ok, i suppose in 2004 there was no tool like this :-)