Mix Shader Factor, dependant on view direction

Hi All,

Firstly thank you to everyone in this community for some of most incredibly helpful stuff I’ve read. It has really helped me no end.

I am still relatively new to all this, so learning as I’m going, and I have a problem I’m trying to solve which I really hope you can help me with.

I’m trying to make a heringbone parquet wood floor, and have a relatively decent result so far, but one major element is missing.

If you look at this real photo:

It shows quite will the effect of this style of floor that you get the stripe effect, where the blocks which are running in line with the viewing angle reflect the light / take on a different visual characteristic to the blocks running perpendicular to the viewing angle.

If you move around the room, the ones that currently look darker that the rest will then from some angles look lighter than the rest, and vice versa.

Could anyone explain to me what is physically happening there, and / or give me some suggestions as to how to replicate this?

Thanks in advance!