Foliage

Setting the meta graph

For this example, we'll be using the following meta graph as base:

To spawn the foliage, we will need to do line traces against a physics scene. Create a new one:

Add a new Generate Marching Cube Collider node to your meta graph, assigning the physics scene you just made to it:

This node will populate the physics scene with marching cube colliders we can use to line trace our foliage against.

Setting up the foliage asset

Create a new foliage asset:

In the foliage asset, switch to the Foliage Graph at the top right:

Add the following nodes:

To convert the Vector2D output of the Generate Halton Position 2D node to a Vector, just drag the Vector2D pin to the Vector one. Make sure to set the Z value to 1000000.0.

Make sure to also assign your physics scene and a mesh.

This graph does the following:

• Generate some 2D positions using a Halton random generator

• Line trace against the colliders we generated earlier

• Assign a mesh to the hit positions

• Render the hit positions

Wrapping up

Back into your meta graph, create the following node:

You should now see spheres being spawned in your level!

If you increase your Distance Between Positions in your foliage graph to 500:

You'll get less dense spheres:

Restricting the spawning slope

To restrict the slope at which your foliage spawns, you can use the following logic:

20 is the max spawn angle in degrees here. This gives you the following (with tuned noise settings):

Controlling foliage density with brushes

Follow Brush & Channels, but keep our current meta graph. This should get you setup with some simple brushes and a voxel channel. Alternatively, follow Installing Example Content.

Add the following nodes at the end of your foliage:

This will query the distance from MyChannel at the foliage position, and only select foliage which are less than 10m away from the brush.

This results in this behavior:

Spawning foliage on foliage

Spawning foliage on foliage is just a matter of outputing foliage colliders into a new physics scene, and tracing against that physics scene.

Make a new physics scene, name it FoliagePhysicsScene:

Duplicate your foliage graph, and add the following at the end:

Make sure to add your new foliage in the Generate Foliage node of your meta graph.

You should be getting something like this:

In your "small foliage" graph, add a new line trace node tracing against our foliage physics scene. Merge the result back into our main attributes:

You should now see foliage being spawned on top of other foliage!

Tips & tricks

• You can create foliage collection to make it easier to reference your foliage in your meta graph

• You can toggle Debug on the line trace nodes. This will show you the traces being done

• Just like with brush assets, you can make foliage asset instances!

• You can increase the LOD of your line traces. Going from LOD 0 to LOD 1 will be ~8x faster