How collider surface values combine
How Unity combines the values of surface properties in a collider pair; for example, how it calculates the friction between two colliders that have different friction values.
Read time 1 minuteLast updated 21 days ago
When two colliders are in contact, the physics system uses the surface properties of each collider to calculate the total friction and bounce between the two surfaces.
In Unity, you use the Physic Material asset to control these parameters. The Physics Material asset is represented in the API by the class.
PhysicsMaterialThe Physic Material asset provides two properties: Friction Combine () and Bounce Combine (). These properties each provide four options to control how the physics system calculates the total friction and bounce between two colliders:
PhysicsMaterial.frictionCombinePhysicsMaterial.bounceCombinePriority | Property | Description |
|---|---|---|
| 1 | Maximum | Use the largest of the two values. |
| 2 | Multiply | Use the product of one value multiplied by the other. |
| 3 | Minimum | Use the smallest of the two values. |
| 4 | Average | Use the mean average of the two values; that is, the sum of both values, divided by two. |
Friction Combine applies to both and Static Friction.
Dynamic Friction
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The properties in the table are in priority order. Unity takes priority into consideration when the colliders in a collider pair have Physic Material assets with different combine settings. For example, if one Physic Material asset’s Friction Combine is set to Average, and the other Physic Material asset’s Friction Combine is set to Maximum, Unity uses the Maximum calculation.