Modifying Landscape LOD


Below is a simple landscape with no particular setup with just a wireframe view to be able to see the LODs.
I don’t know how much polygon is reduced in each step and not even sure if it’s based on percentages but here’s the image:

Say the middle area is the closest to the camera thus no reduction occurring there.

A) Are we able to modify it in a way to make it continue to LOD itself even after the 60% reduction? as you see after 60% reduction the polygons remain that way right to the end.

B) Are we able to change these percentages? for example changing the 60% reduction to 90%.