Isophotes Panel

The Number of Bands sets the number of coloured bands on the surface that will appear for angles between 0 and 180 degrees. The Direction is the direction of the light given as vector (x, y, z). The Colour Scheme refers to the methods used to assign colours to the bands, once the bands have been found. The are self explanatory; Black and white, Four Colours and Rainbow.

See also Analyzing the surface and Patch Display Settings Dialog.