LandscapeLandscape is a highly versatile shader that helps to map textures to terrain and other types of complex models in useful and natural ways, through attributes such as slope, height, image, and noise functions. For example, on a single piece of terrain geometry it could be used to create dusty pile-ups on plateau surfaces, exposed rock faces in steeper cliff-like areas, and water stains where the ground meets the sea. Especially useful in situations where the size or shape of an object makes handmade textures impractical. Landscape works by blending a base color with an overlay color. The blending parameter is computed from one or more effects.Effects The artist controls Landscape by applying one or more different "effects". One such effect, Slope, piles a texture on flat surfaces, like snow piling on a plateau. Height behaves like a waterline. Two different noise generators, Shape Based and Positional, provide natural-looking irregularities. Stain allows the artist to confine a texture with the boundaries of another object. Image allows the Overlay Color's color or alpha-channel to influence its blending. 
Parameters Overall Base Color and Overlay Color are mixed together by a blending parameter computed from one or more effects. Blur controls the sharpness of the border between the opaque and transparent extremes of the alpha-channel. A value of 0 gives a sharp line, a value of 1 gives a very blurred line. Most of the effects apply only on a vertical axis and are dependent on the height above the origin. Use Base Plane Normal and Base Plane Distance to specify the vertical axis direction and distance relative to the world coordinate system origin. Relative to Object and Relative to World controls whether the positions and angles are measured relative to the world coordinate system or the object coordinate system. Relative to World is good in situations where several different objects need a texture to line up across all the objects. Relative to Object is useful when an object needs to move, and the texture must move with it. Also, by rotating the center in Relative to Object mode, effects can be applied at an angle other than the horizontal. Slope Effect The Slope Effect acts like snow piling on a plateau. Flatter areas receive an opaque alpha-channel while steep areas receive a transparent alpha-channel. Active activates the slope effect. Influence is used for mixing. Upside Down reverses the direction of the effect, so that the alpha-channel is opaque in steep areas and and transparent in flat areas. Angle specifies where the cutoff line is, (i.e. how steep the slope is before the snow begins falling off) measured in degrees from the XZ plane. Height Effect The Height Effect creates a horizontal line across the object; areas above the line receive an opaque alpha-channel, areas below receive a transparent alpha-channel. Active activates the height effect. Influence is used for mixing. Upside Down reverses the direction, so that the alpha-channel is opaque below the height-line and transparent above it. Height specifies the height of the dividing line; the line is measured either from the object's center or from the world center, according to the Relative to ... settings. Spread tells how wide the area of effect should be, for blurring and mixing with other effects. Positional Noise and Shape Based Noise The two noise generators provide a way to insert randomness into the landscape. Positional Noise is the noise generator most people are familiar with; it is based upon the surface's absolute position in space. Unfortunately, the noise isn't affected by the shape of the surface, and so can sometimes produce an unnatural pattern. Shape Based Noise helps alleviate this problem by using the shape exclusively as the seed for the noise. This means that as the surface dips and curves, Shape Based Noise will give variations that reflect the change. The drawback comes when two objects have the same shape, they will have the same noise; or when a surface is flat, it will receive no noise.
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