+ // this = bg.getMatrix(this) * bg.master
+ // other = obg.getMatrix(other) * obg.master
+ // this = bindingMatrix * other
+ // this = bindingMatrix * obg.getMatrix(other) * obg.master
+ // bg.getMatrix(this) * bg.master = bindingMatrix * obg.getMatrix(other) * obg.master
+ // bg.master = bg.getMatrix(this)^-1 * bindingMatrix * obg.getMatrix(other) * obg.master
+ // bg.master = XXX * obg.master