Change vector value every tick

I have a simple system with one mesh and a planet like below:

And I make the planet orbit the centre in the least demanding way I found:

Now, I want to change the fake light direction, which is the vector parameter value seen in the bottom, but I have no clue how to make this work. I think I need to (considering this starting position) first increment red and decrement green values, when the first reaches 1 and the second 0, after that R should tend to 0 and G to -1, then R to -1 and G to 0, and in the end R to 0 and G to 1, then the cycle repeats. I have no idea how to make that work and synchronise it with the revolution cycle. Maybe there is a simpler way to do it, I’d really appreciate some clues, hints on what kind of nodes I will be needing, so I can have a start with this thing. I’m not expecting a ready solution.

I previously posted another question regarding this thing, but then I didn’t know how to even use the vector parameter in this BP (now I know I had to construct it first), so this is actually a different issue.

You can use a Timeline with a Color track (Set it to loop and adjust track time). Or manually lerp with the Color Lerp Node. Here a Example I used a simple line to visualize it on screen you would put it into your Vector Parameter of course =)

Edit: you can also rightclick your Color Pin and choose “Split Struct Pin” it will than show you all 4 individual RGBA Pins as floats. Just in case you want to fiddel around them.

Thank you! It’s so simple and works like charm. I made a vector track in timeline with a cycle as I described above (I couldn’t do that with color as it didn’t want to accept negative RGB values) and then I synchronised it with revolution using division of delta time by 2*pi and now it’s perfect for my needs.