Water Shader

The Water Shader is specifically designed to provide a realistic water effect on Terragen surfaces, including wave-shaped displacement, reflectivity, and transparency. Specialized controls are provided to realistically simulate certain water phenomena, for example "wind patchiness".

Waves Tab

Settings

• Roughness: Controls the general roughness of the water surface.
• Wave scale: The average wave size.
• Smallest scale: Determines the size of the smallest details. You may want to decrease this if the water shape looks too simplistic, or increase it if you're only viewing the water from a distance. The smaller this is, the more octaves there are in the Water Shader noise function and the longer render times will be.

• Wind patch effect: In nature, there are variations in wave structure and overall water smoothness across large bodies of water due to wind. This and the next two settings simulate this effect. The "Wind patch effect" setting controls the amount of variation there will be between different areas—effectively the strength of this effect.
• Wind patch size: Controls the average scale of the areas of variation.
• Wind patch sharpness: Sets how sharp the line between areas of variation will be. Put another way, this controls how smooth the transition between areas of different roughness is.

Example movies

Roughness	Wave scale	Smallest scale
Wind patch effect	Wind patch size	Wind patch sharpness

Reflections Tab

This tab controls the reflectivity of the water.

Settings

• Master reflectivity: Controls the overall level of reflectivity for the water.
• Index of refraction: The amount of light refraction caused by a given material, as indicated on index of refraction (or refractive index). 1.33 is the standard refractive index for water. Index of refraction also affects the reflectivity of a surface. The higher this number is, the more reflective the surface will be. It makes the most difference on surfaces that are facing towards the camera (e.g. when looking down at water below the camera).
• Horizon shift: This function is used to simulate the "shift" in reflection due to the aggregate effect of greater or lesser surface roughness on distant reflective surfaces. It will essentially shift the angle of distant reflection toward or away from the horizon.
• Highlight intensity: Controls the strength of specular highlights from direct light sources such as the sun.
• Min highlight spread: Control the smallest amount of "spread" the reflections can have; in other words, how diffuse the reflections are. When rendering with the Standard Renderer this only affects specular highlights of direct light sources such as the sun. When rendering with Path Tracing this may affect the blurriness of all kinds of reflections, but depends on the version of Terragen.

Example movies

Master reflectivity	Index of refraction	Horizon shift
Highlight intensity	Min highlight spread

Sub-surface Tab

Example movies

Transparency	Decay distance	Decay tint
Volume 1 density	Volume 1 colour	Volume 1 density
Volume 1 density funktion	Volume 1 colour funktion

Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.