public CustomTerrainGenerator(ICubicWorld world, final long seed) {
        final int selectorOctaves = 8;
        Random rnd = new Random(seed);
        IBuilder selector = NoiseSource.perlin().
            seed(rnd.nextLong()).
            frequency(8.55515/Math.pow(2, selectorOctaves)/(MAX_ELEV/64.0)).
            octaves(selectorOctaves).
            create();

        IBuilder low = NoiseSource.perlin().
            seed(rnd.nextLong()).
            frequency(684.412D/Math.pow(2, OCTAVES)/(MAX_ELEV/64.0)).
            octaves(OCTAVES).
            create();

        IBuilder high = NoiseSource.perlin().
            seed(rnd.nextLong()).
            frequency(684.412D/Math.pow(2, OCTAVES)/(MAX_ELEV/64.0)).
            octaves(OCTAVES).
            create();

        int heightmapOctaves = 10;
        double heightmapFreq = 200.0/Math.pow(2, heightmapOctaves)/(MAX_ELEV/64);
        IBuilder randomHeight2d = NoiseSource.perlin().
            seed(rnd.nextLong()).
            frequency(heightmapFreq, 0, heightmapFreq).
            octaves(heightmapOctaves).
            create().
            mulIf(NEGATIVE, -0.3).
            mul(3).sub(2).
            clamp(-2, 1).
            divIf(NEGATIVE, 2*2*1.4).
            divIf(NOT_NEGATIVE, 8).
            mul(0.2*17/64.0);

        BiomeHeightVolatilitySource biomeSource = new BiomeHeightVolatilitySource(
            world.getBiomeProvider(), 2*(int) (MAX_ELEV/64), X_SECTION_SIZE, Z_SECTION_SIZE);

        IBuilder height = biomeSource::getHeight;
        IBuilder volatility = biomeSource::getVolatility;

        this.terrainBuilder = selector.
            lerp(low, high).
            mul(volatility.div((x, y, z) -> (y*8/MAX_ELEV < height.get(x, y, z)) ? 4 : 1)).
            add(height).add(randomHeight2d).
            mul(MAX_ELEV).add(64).sub((x, y, z) -> y*8*MAX_ELEV);
    }

    public void generate(final ICubePrimer cubePrimer, int cubeX, int cubeY, int cubeZ) {
        CubePos cubePos = new CubePos(cubeX, cubeY, cubeZ);
        BlockPos start = cubePos.getMinBlockPos();
        BlockPos end = cubePos.getMaxBlockPos();
        terrainBuilder.scaledStream(start, end, new Vec3i(4, 8, 4)).
            forEach(e -> cubePrimer.setBlockState(e.getX(), e.getY(), e.getZ(), this.getState(e)));
    }

    private IBlockState getState(IBuilder.IEntry e) {
        return e.getValue() > 0 ? Blocks.AIR.getDefaultState() : Blocks.STONE.getDefaultState();
    }