Bones warping out of place with Inverse Kinematics

I’ve set up a rig for my character’s arm using Inverse Kinematics so I can controll the whole arm using a controll bone by the wrist. The rest pose has the arm at the characters side, and everything seems to work fine untill I try to move his arm upward so he’s raising his hand in the air. When I do this, the bones in the IK chain start bending and twisting around, and if I keep moving it the whole arm will have rotated a full 180 degrees and be facing backwards. I don’t understand why this is happening, or how to fix it, its probably something simple I’ve never seen before. Does anyone know how I could fix it?

before you joined your rig to your mesh did you do a ctrl n ( recalculate bone roll angles ) on your armature in edit mode? if not, try doing that.

can you post the blend? if you don’t want to post the mesh, you can post the armature.

Are you using a pole target?

I tried that just now, it makes you select between x y and z axis, active bone, view axis, and cursor. I tried selecting all bones and selecting active bone, and it didn’t help. Should I try something different?

I’m not using a pole target, to be honest I don’t know how that works. And how do I post just the armature?

And how do I post just the armature?

Save your file under another name, then delete the mesh, then save again, and post!

The pole vector is an object that will control the twisting of the IK chain.

I messed with the pole target a little, and it seems to have worked, the mesh doesn’t deform anymore. Thanks.