Dividing a circle into thirds..........

Started Sep 12, 2011 | Discussions
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Ralph Ramirez Veteran Member • Posts: 7,001
Dividing a circle into thirds..........

I need to divide this scale 3.5" circle into thirds. I am a Dunce and cannot figure out how to do it in PS. I found these instructions on an Adobe forum but I am unable to follow them. Here are the instructions:

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.

I have included the circle I am trying to divide. Can someone help this old timer out by explaining how it is done? I use CS5.

Thanks............Ralph

joey_B
joey_B Veteran Member • Posts: 3,080
Re: Dividing a circle into thirds..........

Are you sure the forum is about PS? sounds more like an Illustrator thingy.

joey_B
joey_B Veteran Member • Posts: 3,080
Re: Dividing a circle into thirds..........

How I would do this: Draw in Autocad and import as vector shapes in illustrator or PS

Ralph Ramirez OP Veteran Member • Posts: 7,001
Sorry, how do I delete this post?

Sorry, I get carried away sometimes. Is there a way to remove this post?

Ralph

joey_B wrote:

Are you sure the forum is about PS? sounds more like an Illustrator thingy.

Ralph Ramirez OP Veteran Member • Posts: 7,001
Please disregard this post, my apologies..............nt

Ralph

leroyvanhee Senior Member • Posts: 1,828
Re: Dividing a circle into thirds..........

Draw a triangle inside the circle with each side the same length and each point touching the circle.

JJMacks
JJMacks Forum Pro • Posts: 10,311
Don't Have Illustrator I'm a poor man

Photoshop I have and can do
Add a Layer
Use Line tool to draw a radius I put arrow heads on mine.
Duped the layer twice
Ctrl+T free transform moved center mark to circle center entered 120 in angle
selected layer below
Ctrl+T free transform moved center mark to circle center entered -120 in angle

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JJMack

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lylejk
lylejk Forum Pro • Posts: 28,511
Re: Dividing a circle into thirds..........

Well, it took me longer then I wanted it too, but managed to do this. lol

Image hosted free thanks to ImageShack ( http://www.imageshack.us ).

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Mike Warren Veteran Member • Posts: 8,488
Re: Dividing a circle into thirds..........

Mike

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AMAllan
AMAllan Veteran Member • Posts: 4,949
That's a great, simple solution! (nt)
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nand
nand Senior Member • Posts: 2,438
Dividing a circle into thirds with PSCS5

In CS5, hit F8 to bring up the info palette. It will show the drawing angle for a line that is drawn from the center of the circle while drawing with the line tool. The angle shown assumes 0 degrees to be at 3 o’clock on the circle.

For a circle to be divided in three, one line going clockwise 120 degrees and another one counter clockwise 120 degrees does the job.

Nand.
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selwynbr Senior Member • Posts: 1,462
Ralph, why are you apologizing

I'm sure that a lot of us learned something from this post.

RayGuselli
RayGuselli Forum Pro • Posts: 14,462
Re: Ralph, why are you apologizing

Ralph

I am with Selwyn....

Great topic and interesting solutions...

Valuable post!!!!!

Best wishes

Ray

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Vulcanrider Regular Member • Posts: 304
Re: Dividing a circle into thirds..........

Great post! Learned a lot and that's always fun.

Alan

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Ralph Ramirez OP Veteran Member • Posts: 7,001
Wow, so many excellent methods..........

Thank you all. I will try them all then pick the easiest for me. I am responding kind of late because I thought the post was dead. I should have known better, this forum has some wonderful people who are always willing to help. Thank You All, some great ideas.

Best Regards..............Ralph

nand
nand Senior Member • Posts: 2,438
Yet another way again in PSCS5

Since it is a bit of a challenge, here is another one.

Duplicate layer.

Change blend mode to multiply.

With move tool (V), move top layer down half the diameter of the circle as shown. Hold down the ctrl key for better positioning.

With the line tool, draw lines from the center to where the circles intersect. These are the two point that are + and – 120 degrees from the top of the circle.

Flatten image.

The original circle is now divided in thee equal pieces with a 120 degree angle. Color is added for clarity.

Nand.
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Ronny Harris Veteran Member • Posts: 7,069
Re: Yet another way again in PSCS5

Brilliant, nand. I've been pulling my hair out for another solution too. For those who want to know why your method works, the intersection creates an equilateral triangle because all the sides equal the radius. Therefore, the angles have to be 60 degrees. Two triangles = 120 degrees.

Ronny

nand
nand Senior Member • Posts: 2,438
Re: Yet another way again in PSCS5

Thank you Ronny,

I was sort of expecting a solution from you since you usually have one. I hope this one is hard to beat.

Nand.
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Mike Warren Veteran Member • Posts: 8,488
Ronny...

Try this one Ronny :):
http://www.mikedubu.com/mw_one_third_circle.atn.zip

Download the action, load it, then just play the action with no image open.

Make sure your layers palette, info palette and History palette is open (25 steps min.)

As the action runs it will stop 3 times during Transform. Observe the degree setting in the transform control panel. It will be set to 60 degrees the first time, then 120 degrees the next two times. Just click return after each time the transform interface opens. When the action is completed, the 1/3s pie chart will be there in layers. Go back to the first step in the history palette and observe each step thereafter to see the steps used.

The different color wedges could be used to make a pie chart or as a clipping mask with three different images. Not sure what Ralph had in mind for his project...

Mike

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Ronny Harris Veteran Member • Posts: 7,069
Re: Ronny...

Wow! I like that, Mike! Shame on me for not asking you how you did yours the first time around. The nice thing about your approach is that you don't wind up with lines. I practiced your method several times without the action and now I can cut the pie in as many pieces as I want! Thanks for sharing the method that I would use amongst all the suggestions offered thus far. OK, nand and JJ, you have been severely challenged!

Ronny

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