public void addTimeTranslation(float time, Vector3f offset) {
        if (!(time >= 0f && time <= duration)) {
            throw new IllegalArgumentException("animation time out of range");
        }

        Vector3f clone = offset.clone();
        translations.put(time, clone);
    }
Add a keyframe for the specified translation at the specified time.

@param time the animation time when the full translation should be
achieved (&ge;0, &le;duration)
@param offset the local translation to apply to the target (not null,
unaffected)
jme3-core/src/main/java/com/jme3/anim/AnimFactory.java