Why Symmetrize
doesn't work
As explained in Symmetrize — Blender Manual:
Blender needs to know which bones are Left or Right sided. And for this, it uses a naming convention detailed here: Naming — Blender Manual
In short, you need to put variations of left and right. Blender will not recognize anything else, including translations.
A quick fix to it would be to use the Batch Rename tool via ⎈ CtrlF2, set it to Bone, and find/replace and .G
by .L
for example:
Fixing the IK Chains
IK chains rely heavily on how your bones are set up in the 3D space to determine how they should behave.
Bone rolls
If we enable the Armature's axes display, we can see that your limbs' bones are rolled in all directions, which is misleading for IK chains (and also for many animation tools).
To fix this, set your viewport in Front view via numpad 1, select the bones, and press Shift N to open the Recalculate Roll menu. It works by orienting the bones' local Z towards whatever option you chose. In this case I picked View Axis
to easily align all the bones so that they local +Z point away from the viewport, it's a quick and dirty solution but is often good enough.
Chain angles
Then, we will need to look the angle formed by the bones inside the IK chains, that will determine in which direction the two bones will fold when the start/end points of the chain are brought closer. Don't hesitate to exaggerate the angle a bit, it's better to make it big enough to work than not enough.
Pole targets positioning
Then, you have IK pole targets for both your legs and arms. The leg ones are fine, but you place the arm ones in front of the arm. Pole targets should be placed behind the IK chain's angle direction, that's why legs pole target are in front of the knee, and arms pole targets should be behind the elbow:
Besides, the pole target's head should ideally align with the IK chain's point that will point towards the target:
The pole angle
setting
Finally, back in pose mode and select your bones that wear the IK constraints: they have a Pole Angle
setting. Depending how you setup your rig, the IK chain will point at the wrong direction, but you can use this setting to fix that.
If you followed the above correctly, your arm IK should require a Pole Angle of -90
, and your leg 90
:
Final
After that, since we changed names of some bones, your weights will most likely be non-functional anymore. So you will need to remove the Armature Deform modifier on your mesh object, re-parent it to your armature and redo the weights. But the rig itself will work.