Add collision to trees

Colliders define the shape of an object and are used to calculate physical collisionsA collision occurs when the physics engine detects that the colliders of two GameObjects make contact or overlap, when at least one has a Rigidbody component and is in motion. More info
See in Glossary. You can add a colliderAn invisible shape that is used to handle physical collisions for an object. A collider doesn’t need to be exactly the same shape as the object’s mesh - a rough approximation is often more efficient and indistinguishable in gameplay. More info
See in Glossary to a tree asset in the Tree Editor or to a SpeedTree asset in the SpeedTree Modeler.

Set up the terrain to support tree colliders

On the TerrainThe landscape in your scene. A Terrain GameObject adds a large flat plane to your scene and you can use the Terrain’s Inspector window to create a detailed landscape. More info
See in Glossary tile’s InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary window, go to Terrain ColliderA terrain-shaped collider component that handles collisions for collision surface with the same shape as the Terrain object it is attached to. More info
See in Glossary and make sure Enable Tree Colliders is selected.

Note: This option is enabled by default. If you disable it for one tile, other tiles still enable it, including any new tiles you add.

Add a collider to Tree Editor trees

To add a Capsule ColliderA capsule-shaped collider component that handles collisions for GameObjects like barrels and character limbs. More info
See in Glossary to a tree asset, add it to the tree’s prefabAn asset type that allows you to store a GameObject complete with components and properties. The prefab acts as a template from which you can create new object instances in the scene. More info
See in Glossary:

1. In the Hierarchy window, click > next to the tree GameObject to open its prefab.
2. In the prefab’s Inspector window, select Add Component > Physics > Capsule Collider to add the collider.
3. For information on how to configure the collider, refer to Capsule Collider component reference.

To return to the sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary, click < next to the prefab’s name.

The collider is added to the tree prefab, so you can now access it in the Inspector window of the tree GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary. If you’ve already added the tree to the scene using the Paint Trees tool, the collider is added to all instances of the tree.

Add a collider to SpeedTree trees

If you created trees in the SpeedTrees Modeler with collision objects, the Unity Editor accounts for the collision objects when it calculates colliders on the terrain.

For more information, refer to the SpeedTree Collision object documentation.

Additional resources

• Terrain Collider component reference
• Capsule Collider component reference
• Physics Collision