The Derive function computes the absolute values of the texture derivation. The derivation is the difference of a pixel to its next neighbor in horizontal or vertical direction. It is calculated for all pixels of the texture.

Change the Amplify value to regulate the amplitude (brightness) of the derived values.

Define at the Dimensions panel in what directions the derivation process takes place.

Monochrome values are used for the derivation process. They are taken from the Heightmap. Increase the Smoothing value to increase the number of neighboring pixels that are taken into consideration, which results in a smoother result.

The Source Texture supplies the heightmap data.