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So I've been learning lots and getting better at blender. Today I learned about linked objects, and after much research managed to get them to behave as desired using groups.

I'm working on creating a model for the engine for a light cycle, based off this image: http://www.filmedge.net/Tron/hello/SP_lightcycle_engine.jpg

I created two .blend files, one for the basic shape, and the second for the "fins" (the repeated angled blue bits that go from left to right). As you can see this one object is repeated lots, so using linked objects / groups makes sense. By my reckoning there should be 12 of these around the central cylinder. Which means they should be placed at 30 degree angles around the outside.

Googling suggests that you can use the spin dup tool, however that needs to be in edit mode, and because I'm using linked groups, I can't get into edit mode for that. I also read about the mirror modifier, but you can't apply modifies to linked groups either.

Is there a way to do this automatically?

Thanks

EDIT: I've been reading about pivot points, which would at least let me duplicate the group and manually rotate around the correct centre. Except you can't set the pivot point of a linked group.

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I would suggest Array modifier. You need to turn off the two checkboxes for constant and relative displacement, and place an empty on top of the object you want to duplicate. Then, you change the center of rotation to the 3D cursor, then set the empty as the object in the Array modifier, and move the 3D cursor to the center of your model. Increase the number of array iterations by however many objects you want on the outside, then divide 360 by the number of iterations to find out how much you need to rotate the empty. It's a slightly convoluted way of using the array modifier, but it works for me.

Sometimes there will be a freaky scaling problem when you turn on the array modifier, but it can be fixed by pressing ctrl A --> apply scale.

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  • $\begingroup$ Hi Sanix25, thanks for the reply. Unfortunately you're going to have to clarify some things for me. How do you add an empty on top of a linked group? I tried setting the fin's parent to the empty and vice versa, but I couldn't apply a modifier to either of them after that. I tried adding the modifier to the central cylinder, but that duplicates the cylinder around the fin. I tested using a new cube, which I can use the array modifier on, but I couldn't get it to place them symmetrically around the cylinder, only in a line. $\endgroup$ – Andrew Parlane Nov 3 '15 at 13:33
  • $\begingroup$ A linked group? I would join all of the objects in the group that you want to duplicate and join them into a single object by selecting them and pressing ctrl+J. Then, create an array modifier and turn off the two checkboxes for relative and constant displacement. There should be a little text box with a tan object in it down near the bottom of the modifier menu. If you click that and select the empty (which you should spawn at the median of the object you want to duplicate), then it should work. $\endgroup$ – Sanix25 Nov 4 '15 at 16:34
  • $\begingroup$ But make sure to set the 3d cursor as the center of rotation. Down near the bottom of the 3D view screen and above the timeline there should be a little box with different settings for the center of rotation. There should be a selection for 3D cursor. Select that, then place the actual 3D cursor (using the transform menu) at the exact center of the place you want to duplicate them around. Then, rotate the empty a little bit and it should work. If you apply the modifier you won't be able to have one change affect all the others, but you'll be able to delete the empty. $\endgroup$ – Sanix25 Nov 4 '15 at 16:37
  • $\begingroup$ To set the array modifier to use another object, look at the space under the constant and relative sections. There should be a little greyed-out box under the word "Object". Just click the check box next to the word object, then use the text box that appears to select the empty. $\endgroup$ – Sanix25 Nov 4 '15 at 16:40
  • $\begingroup$ If you want to apply the array modifier without joining the objects into a single object, then you're going to need to create an empty and a modifier for each one and it'll be a huge mess. I suppose you could shift-select all the objects and apply a modifier to all of them at the same time then just use a single empty. There might be a simpler way to do it but whatever it is, I haven't found it. $\endgroup$ – Sanix25 Nov 4 '15 at 16:45

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