A physics surface. This is applied to each 
 and controls its physical properties and physics related sounds.
| AudioSurface | 
			Defines the audio properties of this surface for Steam Audio | 
| BaseSurface | 
			Filepath of the base surface. Use <see cref="M:Sandbox.Surface.SetBaseSurface(System.String)">SetBaseSurface</see> and <see cref="M:Sandbox.Surface.GetBaseSurface">GetBaseSurface</see>. | 
| BounceThreshold | 
			Velocity threshold, below which objects will not bounce due to their elasticity. | 
| Dampeningobsolete | 
			 | 
| Density | 
			Density of this surface material. This affects things like automatic mass calculation.
Density is in kg/m^3. | 
| Description | 
			A concise description explaining what this surface property should be used for. | 
| Elasticity | 
			Controls bounciness. | 
| Friction | 
			Friction of this surface material. | 
| ImpactEffectsobsolete | 
			Impact effects of this surface material. | 
| Index | 
			 | 
| NameHash | 
			 | 
| PrefabCollection | 
			Common prefabs for this surface material | 
| RollingResistance | 
			Controls how easily rolling shapes (sphere, capsule) roll on surfaces. | 
| ScrapeEffectsobsolete | 
			Scrape effects of this surface material. | 
| SoundCollection | 
			Sounds for this surface material | 
| Soundsobsolete | 
			Sounds associated with this surface material. | 
| Tags | 
			A list of tags as one string. |