I think you might be misreading the code;
  • The initial Item.Force = Force * Item.Mass calculation is using the global force to perform a scale on the local mass of the object.
  • Thus presenting a basic force vector to representing basic gravity (if in affect).
  • Then inside of the item.gatherforces all other local (constraint) forces are added to this initial value.
  • Integrate utilizes this final force along with the objects mass, last-position, and the time-step to calculate the actual movement of the object for the frame.


Of course, that's if I understand the theory properly