Illuminate the terrain above a certain height in a certain area

Hello, everyone!
I need to illuminate the terrain above a certain height in a certain area

This is essentially the same as Elevation Band Material, but for a specific terrain, not for a scene

Can you tell me where to start?

I’m trying to do something like this (sand castle)
But the notch does not overlap with the relief, and I don’t understand if it’s just a problem or not.

Hi,

Perhaps Classification is what you’re looking to do? You could create an extruded geometry that covers a specific elevation band.