Linking transformation but not other data (ex. Modifiers) in two objects I need to link only the transformation of two objects, but no other properties.
I need to create a hollow cylinder. The catch? It must be made out of cuboid objects and only with rotations 22.5 degrees at a time. This is because I am making this for a Minecraft resource pack, and these criteria are part of the requirements for the Minecraft Exporter I am using. I came up with an idea. I used an empty with a slab I very roughly transform scaled. I copied the transformation info from the slab to the empty, altered the empty so it was 22.5 degrees off in rotation and a bit to the side and down, and then set up an array mod on the slab relative to the empty. This created a barrel.
The problem? Any time I scaled the barrel, the empty had different data, and so the barrel was destroyed in a variety of interesting ways. I tried making the empty a child of the barrel, but then the weirdest thing happened. At first it worked, but if I needed to edit the actual transformation of the barrel slab (ex. to make the barrel thicker), it seemed to reload the parent-child relationship, and give the empty the array modifier. I tried putting both the barrel and empty under the same parent (another empty), which worked but any time I had to rescale the whole thing, I had to select the empty in the hierarchy, not in the viewport, because selecting it in the viewport selected the barrel slab and not the parent empty. So I need to link the transformation of the slab and the empty, but in a way that does not link all properties of the parent.
For arrays from object offset, parent the object to the array.  Empties cannot have modifiers of any kind, so I'm not sure what you're talking about with it acquiring the array.  This is likely a misinterpretation of something, but if it's not, then it's a bizarre bug.  A video of the problem, or a file with explicit instructions to recreate, would be necessary to answer in more detail.

Selecting the empty will not select the barrel.  Regardless of selection in viewport or outliner.  I wish there was an interface to make Blender behave like you describe, it would be useful for a few specialist things.  Again, I suspect you're misinterpreting something, and video or file+instruction would be necessary to give more detail.

To answer the explicit question, for perfect linking of transformation data, use object constraints.  &quot;Copy transforms&quot; copies all data.  You also have &quot;copy position&quot;, &quot;copy rotation&quot;, &quot;copy scale&quot;, all pretty self explanatory.  Generally, you'd be using these world-&gt;world space, but there are times that you could parent an object to an empty and use local space coordinates to achieve other effects.  (However, again, I strongly suspect that there's some misinterpretation of what Blender's doing here, and even though it answers your explicit question, I doubt that it will do what you expect it to.)