Is there a "Mirror Constraint Tool" in Blender, Much Like there is a "Mirror Armature Tool" in Blender's --> Armature -> Editmode? I found the "Copy Constraint" Tool/function But NO "Paste Constraint" Tool/function. And from the methods I've seen online this has to be solved one bone at a time, even with the Copy Constraint Tool used properly.

My .blend file can be found here:


To use the Copy Constraint, you select an object then add a Copy Constraint, then select which other object you want to copy the property from (location, rotation). So no need for paste constraint. For mirroring the armature, you will find x-mirror property in the tools menu in the edit mode of the armature. Just replace the name of the Armature with the name of your Armature.


To do what you want it will be easier to use python. I wrote a script that copies constraint from bones with ".L" to corresponding bones with ".R"

import bpy
context = bpy.context
scene = context.scene
MyArmature = bpy.data.objects["Armature"]
MyArmature.select = True
bpy.context.scene.objects.active = MyArmature
all_bones = bpy.context.selected_pose_bones
for bone in all_bones:
    if ".L" in bone.name:
        boneL = MyArmature.data.bones[bone.name]
        boneR = MyArmature.data.bones[bone.name.replace('.L','.R')]
        boneR.select = True
        boneL.select = True
        MyArmature.data.bones.active = boneL
        if len(MyArmature.pose.bones[boneL.name].constraints) !=0:
            for con in MyArmature.pose.bones[boneR.name].constraints:
               con.subtarget = con.subtarget.replace('.L','.R')

This is how it looks before running the script:

enter image description here

And This is how it looks after running the script where the constraints are copied:

enter image description here

Updated .blend file can be found here:

  • $\begingroup$ To add to Tak's answer adding a if hasattr statement before the last statement will allow his code to work if there are constraints that don't have subtargets, such as a limit location constraint. Here's the line: if hasattr(con, 'subtarget'): $\endgroup$ – Skyler Jyvqh Jul 26 '18 at 2:22
  • $\begingroup$ If you want to ignore KinematicConstraint and TransformConstraint because the code does not mirror the Pole Angle ect correctly. Just put this: if "CopyRotationConstraint" in str(MyArmature.pose.bones[boneL.name].constraints[0]):#Type of constraint to copy. After this: if len(MyArmature.pose.bones[boneL.name].constraints) !=0: you could also: if "KinematicConstraint" not in str(MyArmature.pose.bones[boneL.name].constraints[0]):#Type of constraint to skip $\endgroup$ – ProllySomethingDumb Nov 29 '18 at 12:59

With less Python than the other answer:

  1. From the Armature's Edit Mode, select the bones you'd like to copy to the other side.

  2. Run "Armature" > "Symmetrize". This will copy all the bone settings, including constraints— But it will not always replace the constraints' targets with the mirrored equivalents.

  3. Open a Python Console UI area.

  4. From the armature's Pose Mode, Select the newly mirrored bones, and use a one-liner like below to replace the constraints' targets with the mirrored equivalents:
    [setattr(c, 'subtarget', c.subtarget.replace('.L', '.R')) for b in C.selected_pose_bones for c in b.constraints if hasattr(c, 'subtarget')]

  • 1
    $\begingroup$ There may be some exceptions, but in general, symmetrize will mirror bone constraint targets. Using 2.92. Very handy. $\endgroup$ – Nathan Apr 29 at 19:34
  • $\begingroup$ @Nathan Hm. In my case, the constraints pointed to bones in another armature, so that may be why it didn't mirror them. $\endgroup$ – Will Chen Apr 29 at 21:59

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