Strata

This feature was introduced in the “Artist Point” release

The strata device embeds layers of rock strata (such as from sedimentary rock or multiple volcanic flows) into the terrain. Rock strata is an extremely common and distinctive geological feature.

The more-primitive Terrace device was sometimes used for similar effects in previous versions of World Machine.

How to Use

Add the device to your world, and connect a terrain to the primary input.

Strata will appear with increasing prominence in sloped area such as hills and cliff faces. A completely flat surface will not have any strata exposed on it. A number of useful presets are included.

Parameters

Strata Character Group

• Strength: Controls the amount that the strata lines are exposed or recessed into the terrain. Affected by the Scale parameter below.
• Scale: The typical spacing between major strata layers. The scale affects both the spacing and the exposure distance of the strata. Small scale settings will produce fine strata lines. A large scale will produce dramatic exposed cliff outcroppings and pillars.
• Smoothness: The strata is expressed along the underlying terrain normal. This parameter controls how smoothly that terrain normal varies; increase the value if your strata lines are being broken up by noisy areas, and decrease if you want more detail.
• Layers: Apply multiple sets of strata with decreasing strength. High values will produce many strata layers large and small on your terrain.

Strata Orientation Group

Both of the orientation parameters are spatial, so you can vary them across the map.

• Tilt: Adjust the angle the plane of strata makes with the group. 0 means a flat plane, and 90 is strata tilted completely on its side
• Heading: Adjust the dip direction of the strata lines. 0 means the strata planes tilt to the east. Rotates CCW.

Outputs

• Strata Layers: An ID mask where successive strata lines have different values. Useful for texturing
• Strata Exposure: A mask showing where the strata is exposed on the surface of the terrain

Tips and Tricks

• The two output masks let you effectively texture the terrain by using the strata layer output to drive coloration, and the exposure output to dictate where the strata layers are visible.
• The mask input is very useful in modulating the presence of terraces across the terrain
• The strata device can be ‘abused’ to provide other interesting effects. In particular, it will tend to create columnar/pillowy structures at high strength/low smoothness. The ‘Pillow Columns’ preset shows this effect.

Limitations

The Strata device uses horizontal displacements to achieve its results, which means that it could theoretically cause problems in tiled builds using very low blending percentages. If you notice any artifacts, a higher blend level should completely fix them.

The Strata device is very fast at small scale; increasing the Scale parameter can cause the performance to degrade as large amounts of earth-moving become necessary.