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We know that the there is an Object Offset option for Array modifier, but when trying to make a circular array with that offset object as the center of the array circle, it always doesn't behave quite like what's expected. So how to make a nice and controllable circular array?
P.S.: There is an old trick on CGCookie about moving the object's origin. I wonder if there is any way to do this without changing the location of the origin. :)
Add an empty at the origin of the object that you want to duplicate. (Remember to hit CtrlA and select rotate and scale, to apply transormations on the original object). Then, add an array modifier with object offset linked to this empty.
Set the 3D cursor to the desired centre of the circle. Add another empty here. Make it the parent of the other empty. Now select only the centre empty. Rotate. The amount of rotation is of course dependent on the number of objects, e.g. 12 objects = 30°.
If you want the single elements to "touch" as in your picture you need to either adjust the object width or the radius. The circumference of the circle is 2 * PI * radius, so the width has to be the nth (e.g. 12) part of it. (Or, if it is not about absolute exactness, it can be done visually.)
You probably want to parent the object to the centre empty.
This circle is "controllable" as you can simply change the angle by rotating the centre empty.
Just want to complement with several tricks that I just figured out. They all share with the same idea - to offset the rotation pivot of the Offset Object:
Variant 1:
Using 3D Cursor as pivot. (PROS: Fast and straight forward. CONS: Not suitable for animation)
First, use an empty object in Object Offset section in the Array modifier setting, then, all you have to do is to rotate the empty object, instead of the arrayed object itself:
Variant 2:
Using another object as rotate center.
Note that this variant uses two empties; one at the cube center (just like Variant 1) and one for the pivot point (replacing the 3D Cursor in Variant 1).
To do the actual rotation after setting the Active Element as Pivot Point, first Right-Click the empty at the cube center to select it, then Shift+Right-Click the pivot center empty to select that as well, then R to rotate.
Variant 3:
Parenting.
Variant 4:
Using Pivot constraint.
Variant 5:
Using Hook modifier and Copy Location constraint.
To do that, you would need the arrayed object's origin to be in the same location as your offset object's origin. Try this test:
People have been struggling with Leon's answer. Here is how it works (I'm using default blender scene, with 3D Cursor placed at the origin):
There is a method that actually doesn't require an array modifier:
First figure out how many objects you need, then divide 360 by that number and you have the amount of degrees between each object. For this example, I use a step value of 10 degrees for 36 objects.
Then place the 3D-Cursor in the center of rotation and set the pivot point in the header to 3D-Cursor.
Select your object, duplicate it with SHIFTD and then without even confirming that hit R10RETURN.
That way, Blender considers duplication and rotation as a single action, not two.
You can now use the repeat hotkey SHIFTR to create a full circle of objects and they will be rotated evenly around the cursor.
You can use ALTD to create linked copies instead of SHIFTD if you want to save a bit of memory and filesize. All objects will then use the same mesh.
The advantage of this method is that you have ready to use objects which keep their axes and you save the time for setting up the modifier.
I used blender once to create so called Venetian blinds with an array modifier. To keep rotation of the array objects around there individual origin, I rigged the object to use with the array modifier to a single bone in the center of the object. When you rotate this bone, each object created by the array modifier will rotate around it's own center.
On recent versions of Blender (I'm using 3.0, the name of the node will change on earlier versions), it is possible to obtain a circular array, centered around the original object without creating any empty with Geometry Nodes.
First, add a Geometry Node modifier to your object:
Then go in the Geometry Nodes tab:
Finally, create (using Add/Search) the following nodes (if you don't care about the rotation of your object, you don't even need to specify the Rotation field):
You can then change the number of vertices and radius by changing the properties of the Mesh circle, or change the rotation by tweaking the Align Euler to Vector. The good thing is that you can also save this node and reuse it in multiple places without recreating this graph (in the modifier, simply choose the appropriate Geometry Node in the drop down). For instance, you can change the rotation this way:
What's happening?
Basically, the Mesh Circle creates a "circle" made of N segments centered on the current object. Then Instance on Points will copy the Instance (here our original object) on all the point contained in our Mesh Circle. What is trickier to understand is maybe the rotation. The diamond shape of the Rotation plug means that it is a Field, which means that it waits for a kind of Function (to provide a different rotation for each point). The red nodes (here Normal) are inputs of this function, and this function is evaluated for any point in Points (so basically, here we loop over the points in the circle, and for all of them we take the normal). The Align Euler to Vector part will return the appropriate rotation to ensure that the local X/Y/Z axis of the object (depending on what you choose on the first line) will point towards the Vector field, here the normal of each node.
