Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Collisions
HAIR_COLLIDER_COLLISIONS
Parameter: Friction
HAIR_COLLIDER_FRICTION
Parameter: Bounce
HAIR_COLLIDER_BOUNCE
Parameter: Forces
HAIR_COLLIDER_FORCES
Parameter: Radius
HAIR_COLLIDER_FORCES_OBJECTS_RADIUS
Parameter: Strength
HAIR_COLLIDER_FORCE_STRENGTH
Parameter: Max Strength
HAIR_COLLIDER_FORCES_OBJECTS_MAXSTRENGTH
Parameter: Falloff
HAIR_COLLIDER_FORCES_OBJECTS_FALLOFF
Parameter: Custom
HAIR_COLLIDER_FORCES_OBJECTS_FALLOFF_SPLINE
Parameter: Restrict
HAIR_COLLIDER_LINK
Parameter: Strength
HAIR_COLLIDER_FORCE_STRENGTH_LINK