OptionaldensityMass per unit volume in kg/m³; finite and >= 0.
OptionalfrictionCoulomb friction coefficient; finite and >= 0.
OptionalrestitutionRestitution ("bounciness"); finite and >= 0.
OptionalrollingOptional rolling-resistance coefficient (§25); finite and >= 0.
OptionalspinningOptional spin-resistance coefficient (§25); finite and >= 0.
Construction-time values for a PhysicsMaterial (§25).