Is there a way to convert a constraint to a keyframe? I have a model in Blender with a full rig, including IK bones.
I also have a sword with two bones, on the top bone of the sword I have a set of constraints that copy the location and rotation of a child bone in the right hand. 

The sword is then attached to the hand as expected. The second bone in the sword rig is the target for the left hand constraints that copy its location and rotation. In blender that works as expected. 

I animate the primary rig right hand and the sword and the other hand moves as expected. The problem comes when I import the blender file into unity. 

Unity is only seeing the right hand move but not the left. I can parent the sword to the right hand and it moves as expected. But the left hand data is not changing. 

Back in blender I thought that if I were to select the left hand insert a keyframe (LocRotScale), when there was a keyframe for the right hand, that blender would then save the global position of the left hand, but when the new keyframe was inserted it had an orange line to the previous keyframe indicating that the position had not changed. 

Is there away to get blender to save a keyframe for the left hand when the constraint moves it?
You could use Object > Animation > Bake action
(Or if you are in Pose mode, Pose > Animation > Bake action)



Bake action was added to the menu in Blender 2.62
(though it was previously available with Space> Search)
Unfortunately, there does not seem to be any documentation for this feature yet.