The name of the surface property, identical to util.GetSurfacePropName.

How hard a surface is. If this is greater than or equal to another surfaces's hardThreshold, a hard impact sound will be used.

Hardness threshold for impact sounds. HitSurface.hardnessFactor >= InflictorSurface.hardThreshold - hard impact sound (depends on hardVelocityThreshold's value), HitSurface.hardnessFactor < InflictorSurface.hardThreshold - soft impact sound (always).

Velocity threshold for impact sounds. impactSpeed >= HitSurface.hardVelocityThreshold - hard impact sound (depends on hardThreshold's value), impactSpeed < HitSurface.hardVelocityThreshold - soft impact sound (always).

Amount of sound reflected from the surface represented as a number 0.0 - 1.0. 0 - no reflection, 1 - fully reflected.

How rough a surface is. If this is greater than or equal to another surfaces's roughThreshold, a rough scrape sound will be used.

Roughness threshold for friction sounds. HitSurface.roughnessFactor >= InflictorSurface.roughThreshold - rough friction sound, HitSurface.roughnessFactor < InflictorSurface.roughThreshold - soft friction sound.

Indicates whether or not the surface is a ladder. Used to detect whether a player is on a ladder. 0 - false, > 0 - true.

Scalar multiplier for player jump height - or more accurately, applied z-axis velocity on a surface. For example, 1 - normal jump, 2 - twice as high, and 0.5 - half as high.

The surface material. See MAT enum.

Scalar multiplier for player speed. Achieves this by multiplying CMoveData:SetMaxSpeed in GM:Move.

This is the physical drag on an object when in contact with this surface (0 - x, 0 none to x a lot).

Material density in kg / m^3 (water is 1000). If a surface's density is < 1000, it will float in water. This is used to calculate the total mass of an object.

Collision elasticity - used to compute coefficient of restitution represented as a number 0.0 - 1.0. 0.01 is soft, 1.0 is hard.

Physical friction used to slow entities touching the surface represented as a number 0.0 - 1.0. 0.01 is slick, 1.0 is completely rough.

Material thickness. If this is 0, the material is not volumetrically solid, and thus the object mass will be calculated as "volume * 0.0254^3 * density" where 0.0254 is meters per inch. If non-zero, the mass will be "surfacearea * thickness * 0.0254^3 * density".

Sound to play when a prop or func_breakable is broken.

Bullet impact sound with this surface.

Physical impact sound when hitting surfaces hard.

Physical impact sound when hitting surfaces softly.

Unused sound.

Friction sound when roughly scraping against an entity.

Friction sound when smoothly scraping against an entity.

Footstep sound for left foot.

Footstep sound for right foot.

Unused sound.