Heightfield Shader - Fractal Detail Tab

Heightfield Shader - Fractal Detail Tab

Description:
The settings in the Fractal Detail tab allow you add extra detail to the heightfield. The shader adds extra small scale fractal detail which helps to make up for the limited resolution of the underlying heightfield. Of course the extra detail is "fake" but in many cases this doesn't matter. Here's an example of a heightfield with and without added fractal detail:

Heightfield with (left) and without (right) added fractal detail

You can see the extra detail makes quite a difference. It hasn't changed the overall shape of the heightfield but it has made it look a lot more detailed. The addition of extra detail is not limited to small scale features. You can easily create large procedural features on heightfields as well.

Settings:

• Add fractal detail: Check this to add extra fractal detail to the heightfield.
• Fractal amount: This controls the overall strength (amplitude) of the fractal detail added to the heightfield.
• Fractal scale adjust: This controls the the scale and amplitude of the noise patterns used to add fractal detail. The scale is measure in heightfield data points.
• Fractal variation: The fractal detail algorithm has an internal feedback loop that produces interesting formations that can appear to add variations in strength at small scales. This parameter controls the weight of this feedback, and therefore the apparent contrast of these variations.
• Fractal roughness: This controls the amount of emphasis on smaller scale details. The default value of 1 produces fractal detail which is scale-invariant when considered as displacement. Larger values produce stronger small scale features (making the fractal appear rougher) while lower values produce lower amplitude small scale features (making the fractal appear smoother).
• Fractal flow factor: The fractal detail pattern can be warped by the surface normal of the heightfield data, which may give the impression that it flows downhill or is the result of erosion when used carefully. If there is too much warping this may look unrealistic. This parameter controls the strength of that warping.

Fractal amount	Fractal scale adjust	Fractal variation
Fractal roughness	Fractal flow factor

Back to: Heightfield Shader

A heightmap or heightfield is an array of height values, usually in a grid which describe the height at specific points in a defined area. Heightfields are used to represent real-world and virtual terrain in a specific, easily converted format. Most heightfields can be represented as simple image data in grayscale, with black being minimum height and white being maximum height.

A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.

In general a “procedure” is a series of steps that should result in a specific and reproducible outcome. In Terragen 2 a “procedural” is a mathematical function describing output which may be visualized and sampled to create anything from terrain to clouds.

A parameter is an individual setting in a node parameter view which controls some aspect of the node.

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.