raycast not detecting my mesh from blender

long story short, i imported a multipart mesh as a .blend file, i gave all its parts a rigidbody, mesh collider(convex), and a fixed joint to connect them all together. each individual peice is set to my "Interactive" layer.

then in my player script i do this:

 #pragma strict
 var ray: Ray;
 var hit: RaycastHit;
 var interactionLayer:LayerMask;
 var cam:Camera;
 var camTr: Transform;
 function Start () 
 {
     cam = Camera.main;
     camTr = cam.transform;
     ray = Ray(camTr.position, camTr.forward);
 }
 
 function Update () 
 {
     if(Input.GetButtonDown("Kick"))
     {
         aim();
         if(hit.collider != null)
         {
             Debug.Log("Kick Hit");
             hit.collider.gameObject.SendMessage("Kicked");
         }
     }
 }
 
 function aim()
 {
     Debug.Log("RayShot");
     Physics.Raycast(ray, hit, 2.5, interactionLayer);
     Debug.DrawRay(camTr.position, camTr.forward*2.5, Color.white,2);
     Debug.Log(hit.collider.name);
 }

the "interactionLayer" layermask is set to the Interactive layer via the inspector. this code works perfect on any other object from unity, but when it comes to my custom mesh from blender the raycast just doesnt hit it.

the only debug.log i get is the "RayShot" and then an error because the hit.collider.name was out of bounds. (because of no hit)

can anyone tell me whats going wrong?