> For the complete documentation index, see [llms.txt](https://docs.overthereality.ai/over-sdk-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.overthereality.ai/over-sdk-manual/over-visual-scripting-legacy/nodes/flow/other-events/collision.md). # Collision ### Description This collection of [OverNode](/over-sdk-manual/over-visual-scripting-legacy/visual-scripting-essentials/overnode.md)s represents all the nodes that interact with the physics Unity Collision system. #### Collision Node The main element of this collection consists of a Collision Node, that fires its execution on detecting a specific Collision event. Each Collision Node must refer to a specific `Target` GameObject, accordingly equipped with a Unity [Collider](https://docs.unity3d.com/ScriptReference/Collider.html) Component. Once a collision is detected, the following nodes will be executed. A `Mode` parameter can be selected in order to further customize the execution of the node, specifically:

Name	Description
Enter	Sets the node to be executed when a physical object enters the Target Collider space
Stay	Sets the node to be executed when a physical object stays inside the Target Collider space
Exit	Sets the node to be executed when a physical object exits the Target Collider space

The Node also exposes some parameters, also describing the Collision itself:

Name	Type	Description
Other	Collider	A reference of the input Unity Collider Component of the object colliding with the Target
Contacts	ContactPoint [ ]	List of contact points where the collision occurs
Impulse	Vector3	The total impulse applied to this contact pair to resolve the collision
Relative Velocity	Vector3	The relative linear velocity of the two colliding objects (Read Only)

#### OverCollisionListener In order for the Node system to communicate with the Unity Runtime environment, a OverCollisionListener component must be associated with the Target GameObject. Its main function is to provide a bridge between the node system and the UnityEngine event system, which handles collision events automatically.

#### Collider Exposer This node is used to expose certain parameters and attributes of a given input Unity [Collider](https://docs.unity3d.com/ScriptReference/Collider.html) Component, which are:

Name	Type	Description
Ref	Collider	A reference of the input Unity Collider Component
Object	GameObject	GameObject associated to the collider

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