Resolved Rotate child direction vector around with parent

So I have a child that generates a force in a direction let's say (0,0,-1)[backwards]. If the parent is rotate 90 degrees then to apply that force correct on the child i use this code.

Code (CSharp):

1.   public static Vector3 RotateDirectionVector(Vector3 direction, Vector3 rotation)
2.         {
3.             direction.Normalize();
4.             Quaternion rot = Quaternion.Euler(rotation); // Rotate [angle] degrees about the x axis.
5.             direction = rot * direction;
6.             return direction;
7.         }

However if I have a parent->child->child->child->child then the resulting direction vector of the final child is off a bit off. I know it has to do with the child's parent parent parent affecting the proper rotation however, I'm not sure how to approach this problem.



Any ideas?

 

I justed released the current demo If you want to try out what I currently have working.

Thread link: https://forum.unity.com/threads/dots-dynamic-bones-wip-demo-v8-1-0.1176287/