Mind Body Control - Learning Game AI Programming with Lua - page 219

The bone position
Getting a bone position requires passing a sandbox object or mesh to the Anima-
tion.GetBonePosition function. GetBonePosition also works for any attached
object that contains bones as well. This allows you to retrieve the bone position of a bone
within the weapon while it is attached to the soldier, for example:
local position =
Animation.GetBonePosition(sandboxObject, boneName);