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I am having a trouble mirroring a duplicated object in the Object Mode. The problem is: Ctrl+M only mirrors the object's location but not its rotation.

  1. First I created a cube and used Shift+D to duplicate it.
  2. Then I used Ctrl+M -> x to mirror it essentially about the y-z plane, using the 3-D cursor at the global origin as the pivot point. What I got is shown in the following figure.

enter image description here

The duplicated cube is the one on the LHS after mirroring, but its rotation z value is still the same as that of the original cube on the RHS. What I hope to achieve is shown in the next figure. enter image description here This can be done by manually adding a minus sign to the rotation z value, but it is not practical to do this for every object that I select for mirroring using Ctrl+M in the Object Mode.

I am reading a Blender tutorial book and following the steps in this book. According to the author, I should be able to use Ctrl+M to mirror all the selected objects, inluding their rotation, about the y-z plane in one step in the Object Mode. But when I tried, I had to manually adjust the rotation for the duplicated objects after using pressing Ctrl+M -> x. If I do this for ten selected objects, I'll have to manually adjust rotation ten times and that is not what I hope to do.

I have read many posts online including these two:

Mirroring in Object Mode, taking rotation into account (The object is duplicated using Alt+D, not Shift+D)

Interactive mirror (Ctrl + M) doesn't mirror object (The problem is the pivot point)

I also watched tutorial videos on Youtube. They are not helpful for solving this problem that I have. They do not have a rotated object or they use a modifier that I'm not using. I know that what I hope to do can be done in the Edit Mode for each individual object but it may not be practical to do if I select many different objects. I started to wonder if this operation (using Ctrl+M in the Object Mode to mirror the rotation too) can be done with the current version (v2.83), or if the author of the book wrote something wrong in the book, or if I missed something so obvious that others didn't. If this cannot be done in the current version, I'll simply give up trying (already spent more than 4 hours on this simple step in the book).

Please help. Thank you so much!

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  • $\begingroup$ I have tried and tried, but I can't duplicate your problem. It always works for me, and both location and rotation are mirrored with Ctrl + m. If applying your transforms has no effect on this, the only other thing I could suggest is to close this file and open a brand new one, and perform a new test. It may just work. If you don't want to do that, you could use a Mirror modifier as a workaround, and choose the option that leaves the two halves unmerged. Then separate them afterwards with 'p'. Not ideal, I know. $\endgroup$ – R-800 Jun 28 '20 at 3:19
  • $\begingroup$ Hi R-800. Are you saying that in Object Mode you can mirror an object with rotation z 14 deg about Global x and get a mirrored object that has rotation z -14 (minus fourteen) deg? I can't do that but it is what I hope to do. $\endgroup$ – ACertainNewUser Jun 28 '20 at 5:00
  • $\begingroup$ I have more clarity now. I didn't understand that you wanted the rotation channel values to be numerically inverted and preserved after the mirror. I thought all you cared about was the visual orientation of the cubes, and them being the inverse of one another after mirroring. I could get them inverted by applying all the transforms before mirroring. That works, but it doesn't leave you with -14 degrees on the z axis afterwards for the copy. It leaves you with zero for all transforms, of course. But it LOOKS right. I don't know how to mirror it so that you have inverted transform channels. $\endgroup$ – R-800 Jun 28 '20 at 5:31
  • $\begingroup$ Thank you! The visual orientation is not correct for me either in Object Mode if I use Ctrl+M directly. Emir's solution works for me for now, but still if I apply all transforms the Lattice Deform effect will all be broken. I'm not going to apply transforms for now and hope that won't cause more problems. $\endgroup$ – ACertainNewUser Jun 28 '20 at 5:52
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Not sure if this is what you need, but if you use Collection instance.

-Create a new collection, add the object there

-Right Click on the collection > Instance

-Then right click on the viewport > Mirror >X Global

  • Also, you can add more object to that collection and it's going to have a mirror object automatically

enter image description here

I made a video using this technique for an animation here: https://vimeo.com/417302896 or here (same one) https://youtu.be/deIwRZt-U80

Around minute 3:04. Hope that helps

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  • $\begingroup$ Thank you! It seems that the instance created in your way is linked to the original collection. Could you please tell me is there anyway to unlink or to make the mirrored object independent? I tried to unlink but the instance was deleted automatically. $\endgroup$ – ACertainNewUser Jun 28 '20 at 4:45
  • $\begingroup$ Oh.. It's called "make instances real". Thank you! Your method works for me. I can mirror whatever I want now. Thank you! $\endgroup$ – ACertainNewUser Jun 28 '20 at 5:22
  • $\begingroup$ Yes, indeed. Glad that helps $\endgroup$ – Emir Jun 28 '20 at 15:38

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