Heightfield Smooth Erode

Heightfield Smooth Erode

Overview

This node erodes a heightfield by sampling data points within the area defined by the “Smooth radius” setting then setting the altitude to the minimum or lowest value found within that sample set. The radius value is defined in metres and in world space. It is not dependent on the heightfield’s resolution, ensuring that the erosion effect will be “similar” whether a heightfield's resolution is 1024 x 1024 or 8k.

Fractal detail can be added to the eroded heightfield via the Heightfield’s Fractal Detail tab.

Heightfield fractal detail enabled on top of the Smooth erode process.

Settings:

• Name: This setting allows you to apply a descriptive name to the node, which can be helpful when using multiple Heightfield smooth erode nodes in a project.
• Smooth radius: Sets the maximum distance in metres from the sample point being eroded. The lowest value found in the sample points within this radius is used as the final eroded value.

Heightfield size = 500 metres, Smooth radius = 0.	Heightfield size = 500 metres, Smooth radius = 10 (default).	Heightfield size = 500 metres, Smooth radius = 25.	Heightfield size = 500 metres, Smooth radius = 100.
Heightfield size = 4000 metres, Smooth radius = 0.	Heightfield size = 4000 metres, Smooth radius = 10 (default).	Heightfield size = 4000 metres, Smooth radius = 100.	Heightfield size = 4000 metres, Smooth radius = 250.




The smooth erode effect is independent from the heightfield’s resolution, whether expressed as the “Number of points” setting or the number of pixels in an image file. What matters is the distance in meters which is based on world space. Notice in the example images below that although the heightfield resolutions are very different the final smooth erosion across the terrain looks very similar.

Heightfield resolution 512 x 512, Smooth radius = 0.	Heightfield resolution 512 x 512, Smooth radius = 10 (default).	Heightfield resolution 512 x 512, Smooth radius = 100.	Heightfield resolution 512 x 512, Smooth radius = 1000.
Heightfield resolution 2048 x 2048, Smooth radius = 0.	Heightfield resolution 2048 x 2048, Smooth radius = 10 (default).	Heightfield resolution 2048 x 2048, Smooth radius = 100.	Heightfield resolution 2048 x 2048, Smooth radius = 1000.

A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.

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 sample refers to a value or set of values at a point in time and/or space. The defining point of a sample is that it is a chosen value out of a continuous signal. In Terragen 2 it is usually a mathematical (procedural) function that is being sampled.