Get left rigged hand from the hand rigged hand for Unity


I would like to a pair of independant hands for Unity. I have downloaded a model of a right hand that I have rigged and works fine. I use the .blend file in Unity3D and I have no trouble.

The problem is that now I would like to get the left hand in Unity3D, but everything I attempt to ends either with weird deformations or only scale transformation. It could be nice enough, but in Unity3D I have to modify dynamically the scale values so that the -1 value in the X and Y axes, which change the right hand into a left one, came but to 0.1 and then I get two rights end instead of one left and one right.

In this attempt, I have select all the vertices in Edit Mode, then scale by -1 according to the Y axe. Then I’ve done the same with the armature. I knew that just reverse the object in the Object view would have just change the scale value so I avoided doing so, but it seems I have the same result in Unity as if I had done this.

When I want to de-set the parents, then reverse the right hand (mesh & bones), then set the parent again, it does weird things like the pinky moves the middle of the palm…

I really don’t know what to do.

Sorry if I am not really clear in my explanations.