Biomes are groups of trees and scattering settings, that are used to organize them. They can be broken down into two parts, biome slots, and biome settings.
Biomes work much like materials, in that each object has "biome slots", which are unique for each object (like material slots), and each biome slot can have "biome settings", which work across the whole file, and can be used on multiple objects at the same time, (like materials).
How to use
Add a biome slot by clicking the "+" button next to the biome list.
Add some new biome settings, by clicking on the "New settings" button below the biome list. Alternatively, you can select some existing biome settings from the dropdown on the left.
You can now edit all the settings, such as density and scale, as described below.
If you want to use the same settings on another object, just select that object, add a new biome slot, and select the same biome settings from the dropdown.
On the biome slot, there are two buttons (from left to right):
Show/Hide viewport: Whether to show this biome slot in the viewport. This does not affect the final render.
Show/Hide render: Whether to show this biome slot in the final render. This does not affect the viewport.
Tip: There are some shortcuts you can use to get different results (they work for both viewport and render):
Shift: Toggle visibility of all biome slots.
Ctrl: Invert visibility of all biome slots.
Ctrl + Shift: Isolate. Only show the current biome slot.
The settings row has 5 buttons, which are: (from left to right)
Biome settings selector: This lets you choose which biome settings to use for this biome slot
Name: This is the name of the currently selected biome settings. If it is not changed, it will automatically update when you select some trees to scatter.
New biome settings: Add some new biome settings with default values.
Copy biome settings: Create a copy of these biome settings. The number in its label tells you the number of users that these biome settings have.
You can change all the settings related to scattering in the scattering panel:
Seed: This is the random seed for this biome slot. If two biome slots have the same seed value, the trees will have the exact same placement and randomness. As such, when you add a new biome slot, the seed is automatically increased.
Density: This is the number of trees per square meter area on the selected object.
Scale: The height of the trees in meters.
Scale randomness: The amount that the tree's scale can vary by, in meters.
Spacing: This is the minimum distance between each tree in meters.
Viewport amount: The percentage of trees that are visible in the viewport. This does not affect the number of trees visible in the final render.
Rotation: The Z-rotation of the tree particles in degrees
Tilt: The Y rotation of the tree particles in degrees
Tilt randomness: The amount that the tilt can vary by, in meters.
Camera: When a camera is selected, the trees will automatically turn to face it, allowing for 360° rotation of the camera, without seeing the sides of the tree. It will also automatically cull trees outside the camera field of view to improve performance
Use scene camera: When set, the trees will automatically point towards the active scene camera.
Padding: This is the area around the camera view that won't be removed by the camera culling.
This shows what each setting does visually:
Saving and loading biomes
When you click "Save biome settings" you can specify the name that you want the saved settings to have, and the biomes settings that you want to save.If you select more than one set of biome settings, they will all be exported to the same file.
You can then select all the saved biome setting that you want to load.