public IkConstraint (IkConstraintData data, Skeleton skeleton) {
if (data == null) throw new ArgumentNullException("data", "data cannot be null.");
if (skeleton == null) throw new ArgumentNullException("skeleton", "skeleton cannot be null.");
this.data = data;
mix = data.mix;
bendDirection = data.bendDirection;
bones = new ExposedList<Bone>(data.bones.Count);
foreach (BoneData boneData in data.bones)
bones.Add(skeleton.FindBone(boneData.name));
target = skeleton.FindBone(data.target.name);
}