How to make an rod to rotate with another rod both have pivoting point at the origin Being new to Blender I can not figure out a simple animation using the Animation node. The video link is attached with this post for better expalnnation of the problem (https://drive.google.com/file/d/10aujAJhRNYWZe_4z3lPQtQsWOpRGgCPC/view?usp=sharing).
Here my objective is to rotate the red arrow (YZ_Vec) on the YZ plane while the green arrow (Main_Vec) is free to rotate in all directions. The red arrow will follow the rotation of the green arrow while being confined on the YZ plane.To make the red arrow confine on the YZ plane I have applied the limit rotation constraint.
With the help of animation node I have successfully achieved my objective partially, because the red arrow perfectly follows the green arrow during the X rotation but not during the Y rotation.
During the Y rotation the red arrow rotates in opposite of the green arrow. I am expecting the red arrow should moves on the YZ plane during the Y rotation of the green arrow, that would look like the red arrow goes up and down on the YZ plane with the Y rotation of the green arrow.
There's no need for Animation Nodes, here, unless you have reasons. You can used a Locked Track constraint on the red arrow.
Here, an Empty has been parented to the tip of the green arrow, for the red arrow to follow. The red arrow has been given a Locked Track constraint as follows:

.. so it points its own X axis at the Empty, while constrained to the plane whose normal is its own Z. (Apologies for the axes not being the same as yours, you'll just have to swizzle them). The green arrow is free to rotate...

...the red arrow points in the direction of the green arrow's projection onto  the red arrow's XY plane.