public static Vector3f extrapolateLinear(float scale, Vector3f startValue,
            Vector3f endValue, Vector3f store) {
        if (store == null) {
            store = new Vector3f();
        }
//        if (scale <= 1f) {
//            return interpolateLinear(scale, startValue, endValue, store);
//        }
        store.x = extrapolateLinear(scale, startValue.x, endValue.x);
        store.y = extrapolateLinear(scale, startValue.y, endValue.y);
        store.z = extrapolateLinear(scale, startValue.z, endValue.z);
        return store;
    }
Linear extrapolation from startValue to endValue by the given scale.
if scale is between 0 and 1 this method returns the same result as interpolateLinear
if the scale is over 1 the value is linearly extrapolated.
Note that the end value is the value for a scale of 1.

@param scale the scale for extrapolation
@param startValue the starting value (scale = 0)
@param endValue the end value (scale = 1)
@param store an initialized vector to store the return value
@return an extrapolation for the given parameters
jme3-core/src/main/java/com/jme3/math/FastMath.java