Given that I have a an imported Blender model, consisting of a cylinder Mesh, and two connected Bones, each half the Mesh length (and vertices weighted accordingly):

How do I rotate the end Bone towards a selected target's position, such that the associated Mesh points towards the target?

When I first created the model in Blender, they were all aligned on the Z-axis, with no rotation. When I saved them to a .fbx file, I specified no rotation on any axis. For whatever reason, the children GameObjects all have a different orientation than the top-level GO.

After importing, my Hierarchy looks like this:

oneTube (GameObject: standard rotation, x=0, y=0, z=0)
- - armature (GameObject: rotation of x=0, y=180, z=0)
- - - - oneBone (GameObject: rotation of x=90, y=90, z=0)
- - - - - - twoBone (GameObject: rotation of x=0, y=180, z=180)

Things I have tried, and couldn't get to work:

The LookAt() function:

twoBone.transform.LookAt(tmpTarget.transform.position);

The LookAt() function on the target in the Bone's Local Coordinate Space:

Vector3 invPos = twoBone.InverseTransformDirection(tmpTarget.transform.position);
twoBone.transform.LookAt(invPos);

Assuming that the Bone object was facing along its Forward vector, and rotating from there:

Vector3 invPos = twoBone.InverseTransformDirection(tmpTarget.transform.position);
Vector3 newDir = invPos - twoBone.position;
Quaternion newRot = Quaternion.FromToRotation(twoBone.forward, newDir);
twoBone.rotation = newRot;

I also tried all three axis vectors up/right/forward, none of which worked. And I tried using the Normal to all three axis vectors, again no joy.

Which brings up another question - what direction is the Bone considered to be facing? How can I determine that from its Transform?