public Vector3 Drag(Vector3 localVelocity, float dynamicPressurekPa, float mach) { Vector3 drag = Vector3.zero; for (int i = 0; i < count; i++) { SimulatedPart part = parts[i]; drag += part.Drag(localVelocity, dynamicPressurekPa, mach); } return(-localVelocity.normalized * drag.magnitude); }