Incorrect armature mirroring due to improper rotation/scale application.

(I apologize for coming here only when I have problems. Apparently I don’t know how to google this problem, as doing so gives me unrelated hits.)

I’m running Blender 2.75, using the Pitchipoy Human Meta-rig.

When I try to manipulate a bone on the right or left side (with X-axis mirror enabled), its mirror’ll pop over to the side I’m manipulating. ※However, there’s no problem with the mesh mirroring (using the mirror modifier and X-axis enabled).

I think this problem manifested after I applied rotation, scale, location of the “finished” armature.
(Or maybe I hit some kinda hotkey.)

(Edit: I’ve deleted the model)

If any kind soul could tell me where I went wrong, it would be greatly appreciated.

(In the interim I’m going to redo the rig and leave this as an unresolved mystery. I’m pretty sure this can be fixed relatively quickly. I prolly did something stupid. I doubt it’s a bug…)

Your model and armature are oriented with their intended X axis on the world’s Y axis. For most operations/tools, you can consider object mode rotation to be your way of telling Blender where left, right, up and down are relative to Blender’s world. By applying the object mode rotation, you’re essentially telling Blender “the left/right of the meshes inside of this object is the same as the world’s.” Since you applied with the mesh rotated 90 degrees from your intent(I assume), now Blender is mirroring your model on the world’s X axis instead of our idea of the model’s X axis.

If you wanted to work on that axis for whatever reason, applying the rotation was actually a bad idea in this case, assuming the model was originally oriented with its width/wingspan on the world’s X axis. Either way, yes, it’s an easy fix. Just rotate it so that it’s oriented with its face facing the XY plane, apply, then rotate back(and don’t apply).

Awesome. Thank you wtflux (cool handle).
For some reason I thought I had to invoke an unapply scale/rotation/location command to get it working as normal. Setting it back to the default blender orientation and applying scale/rotation/location, as you so suggested, worked perfectly. Thank you very much.

A couple times in the past I’ve run into probs as a result of failing to apply scale before doing some other kind of forsaken routine. So to avoid potential probs in this case, I did it for bad measure.

For the record, having seen this tutorial on importing blender models into UE4 (https://www.youtube.com/watch?v=aC1_m0VdKIY
I decided to have the model (and a bad one at that) face down the +x axis right from the start, rather than the default blender -y axis.

Something interesting I noticed is that, having done that, the mirror modifier for the mesh (not the armature) only has the X axis enabled, yet everything mirrors perfectly even though I had applied rotation with this (biped) mesh “facing” down the +x axis - with the intended mirrored vertices running across the y axis.

Sorry for the diatribe. But thank you very much, wtflux. You saved me a good 40 minutes or more. I hope you didn’t take too long to write that awesome reply. I changed the title of the post and added a little more info to explain the sitch.

Thanks again! Extremely appreciated. I’ve learned something thanks to you.