Unity Terrain Pro
In order to add a terrain to Vegeation Studio Pro it needs access to a component implementing an interface. This is done to have a common interface for multiple terrain types making it easier to extend and support terrain types.
To use a standard Unity terrain add the UnityTerrain Component to the same GameObject as the terrain. You can then add the terrain to the Vegeation System Pro component.
When a component is added it will store the position of the terrain. This is used for floating origin when terrains is loaded run-time. If you create the component run-time in code you need to set this terrain position to the terrains origin.
Add/Remove at Enable/Disable
For setups where you load and unload terrains run-time check this box. When loaded the component will auto register with the VegetaionSystemPro component in the scene. Remember that autocalculate area has to be turned off on the terrain tab of the VegetationSystemPro component to use this.
Disable Unity trees/details
When enabled this will disable draw on Unitys trees and detail. This is enabled by default since Vegetation Studio does its own rendering of Vegetation
Terrain Source ID
This setting gives the terrain an ID. This ID can be used for spawning rules. A vegetation item that only grows on one terrain etc. The same ID exists on the other terrain types.