Understanding transform.rotation

I didnt unterstand why this funktions giving back different values. I also didnt find an explanation in the documentation
can someone explain to me why this:

Code (CSharp):

1.         pos += transform.rotation * velocity;
2.         Debug.Log(pos);

gives back another value than this:

Code (CSharp):

1.         pos.x += transform.rotation.x * velocity.x;
2.         pos.y += transform.rotation.y * velocity.y;
3.         pos.z += transform.rotation.z * velocity.z;
4.         Debug.Log(pos);

_______________

Im looking for a way that in my 2D shooter the bullets get effect by the current movment of the player.
i think i have a way by using the player.GetRelativePointVelocity(nullpoint);

my problem is that im not able to add it to the bullet movement.

Code (CSharp):

1.         if (plMove == new Vector3(0f, 0f, 0f))
2.         {
3.             plMove = movment.GetPlayerRelativeMov();
4.             plMove = plMove / 50;
5.         }
6.         Vector3 totalVelocity = velocity + plMove;
7.         Vector3 pos = transform.position + plMove;  //this is the problem line
8.         pos += transform.rotation * velocity;
9.         transform.position = pos;

 

https://starmanta.gitbooks.io/unitytipsredux/content/second-question.html

 

Because rotations are not vectors, but quaternions.

And quaternion-vector multiplication is not defined the same way as vector-vector multiplication. When you multiply a quaternion and a vector together, you're rotating the vector. When you multiply a vector by another vector, you're scaling it (often non-uniformly).

 

Thank you now it is working well.
Im now just adding the playermovement to the y coordinat of the velocity

Code (CSharp):

1.         Vector3 pos = transform.position;
2.         if (velocity == new Vector3(0f, 0f, 0f))
3.         {
4.             plMove = movment.GetPlayerRelativeMov();
5.             plMove = plMove / 50;
6.             velocity = new Vector3(0f, 1f, 0f);
7.             velocity.y = velocity.y * BulletSpeed.y;
8.             velocity.y = velocity.y + Mathf.Abs(plMove.x) + Mathf.Abs(plMove.y) + Mathf.Abs(plMove.z);
9.             Debug.Log("mov = " + plMove + "   Vel = " + velocity);
10.         }
11.         pos += transform.rotation * velocity;
12.         transform.position = pos;