The compositor node group can be appended to your project or used directly from the provided blend file. The node group takes a height map and return the normals of the surface represented by that map. Other types of maps—like diffuse maps—can be used, in which case, they are treated as height maps through conversion to greyscale.

The only available input is the multiplier input which gets multiplied to the input height map controlling its rate of change. In other words, it controls the strength of the normal map where negative values invert the normal map.

When using highly detailed high resolution images, the generator will try to capture all of the details resulting in a rather noisy normal map. Such maps may not always be desired, instead, one might choose to ignore those high frequency details and enhance the low frequency ones. In which case, a blur node can be used where the blur radius controls the amount of details one wants to capture. Additionally, one might use an RGB Curve node to further tune one's output.

It is advised to use the combination between the blur and RGB Curve nodes for fine control over the output where bluring controls the amount of details and RGB Curve controls the level of details as noted in the foregoing example.