Vegetation

The vegetation tool lets you paint trees, plants, rocks, and other items onto a landscape to quickly create entire forests. It can be accessed by selecting the Terrain Panel and then selecting the Vegetaion tool in the Tool drop-down box.

Like terrain materials, vegetation is separated into separate layers, each with its own properties. Each layer can contain one or more variations. These are usually different versions of a model that help to create a more random look to the scene and prevent repetition. The variations are randomly selected by the vegetation system.

The vegetation system can support very large numbers of objects with minimal memory usage and fast performance.

Adding Vegetation Layers

To add a new vegation layer to the terrain, press the Add button at the bottom of the vegetation panel. Select the Add Layer popup menu. An file open dialog will appear, allowing you to browse to and select a model file to use for the vegetation layer. If you select multiple model files with the file open dialog, each model will be added as a variation in the new layer.

Once the vegetation layer is added, you can begin painting it onto the landscape. With the vegetation layer or a variation selected in the list, click and hold the left mouse button on the terrain. Drag the mouse across the terrain to create instances of your layer.

If you hold the Control key while painting, the vegetation tool will act as an eraser to remove instances from the terrain.

Layer Properties

Each vegetation layer has the following adjustable properties.

Name: The name displayed in the vegetation layer list.

Seed: A random seed for calculating the orientation of instances. You can change this value to produce a different orientation for all instances in the layer.

Density: The average distance between instances in the layer. You can use this to spread instances apart, or pack them more tightly together.

Min slope: The minimum terrain slope, in degrees, above which instances can appear. This can be used to only make cliff rocks appear on the sides of hills, for example.

Max slope: The maximum terrain slope, in degrees, below which instances can appear. This can be used to prevent grass from growing on the side of a cliff, for example.

Min height: The minimum terrain height, in meters, above which vegetation instances can appear. This can prevent plants from growing underwater, for example.

Max height: The maximum terrain height, in meters, below which vegetation instances can appear. This can be used to create a tree line, above which no trees can grow.

Variation Properties

Each vegetation layer variation has the following properties that can be adjusted independently from other layer variations.

Model: Selects the model to use for the variation.

Alignment: You can choose center (the default) mode, per-vertex, or rotate to normal.

The per-vertex mode is useful for making grass align precisely to the terrain.

The rotate-to-normal model is useful for making rocks rotate to the slope of the terrain they are resting on.

Pick mode: Controls the pick mode of the instances, for ray casting operations.

Weight: A percentage value indicating how likely this variation is to appear. This can be used to ensure that a very unique variation of a model that stands out a lot will get used less frequently. The weights of all layer variations will be normalized automatically.

LOD range: This provides control over the distances at which the instances will change LODs, if the model contains multiple levels of detail.

View range: This controls the maximum distance beyond which the instances will disappear from view.

Shadow: This can be used to enable or disable shadows on the model.

Collision: This indicates whether the instances are collidable with physics. To be interactive, the model must also include a collider.

Nav obstacle: This indicates whether instances of the model interact with the navigation mesh system. To be interactive, the model must also include a collider.