Rigify/Armature - additional bones cause unwanted deformation I made simple humanoid low-poly character/model for testing/prototyping.



Character has extra "weapon" bones attached to palms. The idea is to parent weapon objects to those bones, which would allow me to rotate blades/guns/whatever independently from hands.



However, once I create "rigified" rig, rotating those bones (which show up at FK layer, by the way) cause unwanted deformation of fingers.



I checked mesh in weight paint mode, this is not problem with weight, actual skeleton is being deformed. (It is visible in the last screen).

Why does this happen, how do I fix this, and is there alternative/better way to make "weapon" bone? 

I do suspect that "weapon bone" somehow interferes with inverse kinematics, but I'm not sure how to proceed from there. 

Model is animated with inverse kinematics, with all FK/IK sliders set to IK on arms/legs.

I created weapon bones by selecting "hand", extruding it twice, then deleting middle connecting bone.

Aside from having extra bones for weapons, it is pretty much stock metarig with slightly adjusted bone positions.

I'm using 64bit blender 2.74 on windows 7.



Here is file with the rig (without geometry/animations). It is saved with weapon bone selected.
Your ORG-palm.0# finger bones (the base ones) have constraints copying transforms from the ORG-weapon bone.

The constraints were probably targeting different bone originally (hand probably).

Delete those constraints or re-target them to ORG-hand.

Why don't you use Child-Of constraining for picking up objects/weapons? I think you don't need the weapon bone, this seems very non-standard.