# Sandbox.Physics.CollisionRules

This is a JSON serializable description of the physics's collision rules. This allows us to send it
to the engine - and store it in a string table (which is networked to the client). You shouldn't really
ever have to mess with this, it's just used internally.

- Kind: class
- Namespace: `Sandbox.Physics`
- Assembly: `Sandbox.Engine`
- Inherits: [Sandbox.ConfigData](/api/Sandbox.ConfigData)

## Constructors

- [`CollisionRules`](/api/Sandbox.Physics.CollisionRules/.ctor)

## Properties

- [`Defaults`](/api/Sandbox.Physics.CollisionRules/Defaults): If no pair matching is found, this is what we'll use
- [`Pairs`](/api/Sandbox.Physics.CollisionRules/Pairs): What happens when a pair collides
- [`SerializedPairs`](/api/Sandbox.Physics.CollisionRules/SerializedPairs): Gets or sets [Sandbox.Physics.CollisionRules.Pairs](/api/Sandbox.Physics.CollisionRules/Pairs) in its serialized form for JSON.
- [`Tags`](/api/Sandbox.Physics.CollisionRules/Tags): All tags with either an entry in [Sandbox.Physics.CollisionRules.Defaults](/api/Sandbox.Physics.CollisionRules/Defaults) or [Sandbox.Physics.CollisionRules.Pairs](/api/Sandbox.Physics.CollisionRules/Pairs).
- [`Version`](/api/Sandbox.Physics.CollisionRules/Version)

## Methods

- [`Clean`](/api/Sandbox.Physics.CollisionRules/Clean): Remove duplicates etc
- [`GetCollisionRule`](/api/Sandbox.Physics.CollisionRules/GetCollisionRule): Gets the specific collision rule for a pair of tags.