@Override
    public float value(final float x, final float y, final float z) {
        return ImprovedNoise.noise(this.scale * x, this.scale * y, this.scale * z);
    }
Perlin's default implementation of Improved Perlin Noise
designed to work with Noise base
jme3-terrain/src/main/java/com/jme3/terrain/noise/basis/ImprovedNoise.java