How to perfectly mirror a set of objects on one axis

Hello.

Im currently making a robot arm which consists of many different parts. I finished the left arm in terms of modelling, rigging and basic materials. In order to get started working on the bigger project this belongs to I want to make a first working version of the arms, so I wanted to mirror the left arm over to the right side and redo the rigging for that side. The rig is just the regular metarig with everything but the arms removed, so it already had both sides.

However when using the regular mirror tool, the left arm only gets partially mirrored correctly over to the right side. Everything seems to be in the right place, but the lower part of the arm has messed up rotations ( see fingers and lower part of the arm in the attached picture ).

I used the 3D cursor right in the middle as the mirror point and the regular mirror option when looking for “mirror” in the search box.

Images of the problem:

image

Does anyone know a way of doing this without me breaking the rotations like that or a way of fixing this perfectly? Id rather not manually adjust this, since it wouldnt be a “perfect” mirror anymore.

See “Mirror Object” option, make an Empty at the origin and use that for all of your objects.

im not using the mirror modifier but the mirror operation. I actually want separate objects

Sure, you can then apply the mirror modifier then you have separate objects. You do not have to keep your modifier.

its still one object when I apply it. I just gotta separate it manually after if I use your method. I mean it would WORK just is tedious work. Is there a better method?

Try putting all your objects under an empty, duplicate the hierarchy and mirror or scale the empty on x -1. Then unparent them keeping the transforms.

In such cases you really need to plan ahead basically.

Hard to tell without seeing the actual blend files.

hm. interesting suggestion, however i think that would invert the UV mapping too …

Im about to finish it anyways. I did the mirror modifier now, applied it and am currently seperating, renaming and fixing all the origins of all the parts. Im almost done. I really should have planned ahead

That is the spirit!

Btw it should not mess up your uvs, they work in different dimension unlike regular projects.

Thanks for your help!
Final product:


I am glad it worked out.