Lerp factor between 2 vectors? (maths problem)

[FoamingGoat (ThatMarcusBoy)]

Hello there! I’ve got a little maths problem that I’d like help with.

I have the sun vector, and then the vector of 2 planes, one plane is facing away from the sun (same general direction) and the other is pointing towards (opposite general direction). I want to lerp something depending on this but don’t know the math to do between the sun and object orientations.

I’m just trying to lerp POM shadows out at extreme / opposite angles.

Any thoughts? Thank you!

[ClockworkOcean]

Something like this should do it, I think

I’m lerping between shadows and no shadows ( might have to swap them over )

( Can also use vertex normal, of course )

[FoamingGoat (ThatMarcusBoy)]

Perfect! Of course it’s so simple.
Thank you Clockwork, a credit to the community!