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Cal­cu­late mul­ti­ple objects in a cir­cle in Illustrator

When you are draw­ing or design­ing in Illus­tra­tor you prob­a­bly at one time or another need to put mul­ti­ple objects in a cir­cle. This is basi­cally very easy by using the rotated tool, click some­where you want the cen­ter of rota­tion to be and drag the object while you hold the mouse. Repeat this process over and over or sim­ply do Object > Trans­form > Trans­form Again or even Com­mand + D.

This method is fine when no pre­ci­sion is needed. But lets say you want to make a draw­ing of a clock or a watch or sim­i­lar. There you might want to put one object twelve times in a cir­cle to mark every five min­utes and even have another object to indi­cate every minute sixty times in a cir­cle. And to make this a bit more com­pli­cated, maybe you want to be able to edit those objects after you have placed them in a cir­cle with­out hav­ing to do every­thing over again if you need to change.

This is all very doable in Illus­tra­tor. I am going to walk you through three dif­fer­ent meth­ods and point out some advan­tages and dis­ad­van­tages in every one of them. In the end I am going to show you a cal­cu­la­tor I made to help you make this very precise.

The first method is very sim­i­lar to the one I men­tioned in the begin­ning but we can be much more pre­cise with very lit­tle extra effort.

First, drag one hor­i­zon­tal and one ver­ti­cal guide lines into the art­board. Where they cross will be our cen­ter of rota­tion. Draw your object at the top and keep the object cen­tered on the ver­ti­cal guideline.

While the object is selected, choose the Rotate tool by hit­ting the R but­ton on the key­board. Hold down the Alt/Option key and click once where the guide­lines cross. This will bring up a dia­log box where you can type in the degree you want the object to be copied by. You might know that twelve objects need to be 30° apart but if not, type in 360/12 and hit the Tab key once to con­firm. Illus­tra­tor will instantly cal­cu­late the degree for you. Hav­ing the Pre­view on shows you the move­ment and when you hit the Copy but­ton the first copy is made. Hold down Com­mand + D until the cir­cle is filled. Great isn’t it?

The dis­ad­van­tages here are that hold­ing down Com­mand + Z will not undo in the same way or speed as Com­mand + D made the copies. You have to click for every object made if you change your mind or have made some mis­takes. Which is fine for 12 objects maybe but not 360. And sec­ondly, if you want to change the shape of the objects you have to do this all over again which can be a pain. It is there­for nice to make the 12 objects on a sep­a­rate layer and the 60 objects on another to eas­ily remove any parts you like in one go. But this is the nice and easy way to go when you only need to do this once in a while.

The sec­ond method is exactly like the first one, except that when you have placed the object at the top you drag it to the Sym­bols panel and then do the rest. This means that what you rotated are instances of that sym­bol in the Sym­bols panel and thus can be edited. You can select the ones you want to change and choose a dif­fer­ent sym­bol or you can make a new object and Alt-Drag it over the sym­bol you just used and all will be replaced.

This is a clever and use­ful way to use Sym­bols but still it’s not the per­fect way if lets say you are a pro­fes­sional watch designer.

The third method and in my opin­ion the best is to use the Trans­form Effect. Still it is miss­ing some vital con­trols but I have solved it and made an online cal­cu­la­tor to over­come its shortcomings.

Select your top object and go to Effects > Dis­tort & Trans­form > Trans­form… Start by check­ing the Pre­view box The big dia­log box allows us type in how many copies we need, in our case we need 11 copies. Then down left we can let Illus­tra­tor cal­cu­late 360/12 to get 30° (or 360/60 for the min­utes etc…) By now we can see all our instances in one bun­dle cen­tered together.

Then we need to move the Hor­i­zon­tal and Ver­ti­cal Move slid­ers to add the spac­ing between the objects and this is where the prob­lem begins. Prob­lem one is that there is no obvi­ous way to deter­mine the over­all width of our cir­cle nor the radius. I have asked some of the folks who spe­cial­ize in Illus­tra­tor and how to set this the way that the 9 and 3 objects and 12 and 6 objects align (I am refer­ring to the posi­tions of the objects). The answer has always been: Put the same num­bers into the Hor­i­zon­tal and Ver­ti­cal values.

This is true, yes, but play­ing with pos­i­tive and neg­a­tive num­bers always turns out that the orig­i­nal object is in one of these posi­tions: 2, 5, 8 and 11.

In this exam­ple set­ting four objects with the val­ues to 20 and 20, pos­i­tive and neg­a­tive, the instances go from posi­tion 8 and we would have to rotate the object itself also after­wards by 120° to straighten things up. Besides, as you see the objects here are placed where I planned to have as the posi­tion 12 and find­ing the cor­rect posi­tion would be a pain again. And it stretches out of my artboard.

Not totally unus­able but it could be far bet­ter. The way Trans­form Effect works, you can edit the orig­i­nal object and the instances will change accord­ing. But it is not so easy to work with even sides at 30 degrees when the object is always tilted. Besides that, mak­ing the objects fill a cir­cle of a cer­tain size can only be found by trial and error as far as I can see.

I still want my main object to be placed at the top for easy edit­ing and I want to be able to set the exact size of the cir­cle. This is where the Illus­tra­tor­Cir­cle­Cal­cu­la­tor comes in. The cal­cu­la­tor uses the same para­me­ters as you use in the Trans­form Effect dia­log box but adds the diam­e­ter of the cir­cle you want to use as a main ele­ment in the cal­cu­la­tion. And every­thing fits per­fectly and you can freely edit your one top object and all the instances update on the fly.

All you have to do is to fill in the diam­e­ter of the cir­cle and the num­ber of objects that you want on the cir­cle and you get the Hor­i­zon­tal and Ver­ti­cal val­ues you need to fill in to make every­thing fit.

I am not sure if any­one cares to know the math behind this cal­cu­la­tor but here is a pic­ture which I used when I was fig­ur­ing this out.

The V and H on the red tri­an­gle are the mea­sure­ments we are after. Know­ing length of the longest side, L, and the degree of the sharpest cor­ner, V is the COS x L and H is SIN x L.

The length of L is two times the short­est side of the brighter green tri­an­gle which has half of the degrees to the first instant.