View reference: reading actual node information and pass it as a parameter. PHP needed.

I have a content type called "Painting", this Painting includes a custom field pointing to a view (a "contextual view" in this case). I use this field to see all the Authors paintings.

If I want that the "contextual view" it's ok then I need to pass a parameter, the Author Id (it's contanined in the Node).

As a (node) example:
- Painting name: "MonaLisa" (text field)
- Author: "Da Vinci" (taxonomy term)
- paintings_by_author (View reference)
- 5 (View parameter. Let's suppose that "5" is the number assigned to my "Da Vinci" taxonomy term).

In this way, it works.

The problem is that I have to find out the taxonomy term for every term, and this info is already in the Node. And this is not a dynamic solution ;)

In order to pass the argument I can use PHP, then, I need to "recover" the actual node info and pass it as a parameter. In a really simplistic way I need something like:

  echo $actual_node->author_id.value;

Can anybody help me?

Thanks in advance.