 AnimatorClasses["linear"] = LinearAnimator
 AnimatorClasses["bezier-curve"] = BezierCurveAnimator
 AnimatorClasses["spring-rk4"] = SpringRK4Animator
+AnimatorClasses["spring-dd"] = SpringRK4Animator
 AnimatorClasses["spring-dho"] = SpringDHOAnimator
 
 AnimatorClasses["spring"] = AnimatorClasses["spring-rk4"]

AnimatorClasses = {}

AnimatorClassBezierPresets = ["ease", "ease-in", "ease-out", "ease-in-out"]

class exports.Animator


				curveOptions.values = parsedCurve.args.map (v) -> parseFloat(v) or 0

			if animatorClass is SpringRK4Animator
				if animatorClassName is "spring-dd"
					dampingRatio = parseFloat parsedCurve.args[0] ? 0
					duration = options.time ? 1
					mass = parseFloat parsedCurve.args[1] ? 1
					velocity = parseFloat parsedCurve.args[2] ? 0
					curveOptions = computeDerivedCurveOptions(dampingRatio, duration, velocity, mass)
				else
					for k, i in ["tension", "friction", "velocity", "tolerance"]
						value = parseFloat parsedCurve.args[i]
						curveOptions[k] = value if value

			if animatorClass is SpringDHOAnimator
				for k, i in ["stiffness", "damping", "mass", "tolerance"]
