Will Replacing Terrain With Air Reduce Lag?

[megmavens5]

Hello there!

When I was building terrain today, I noticed a new feature (I have no idea if this is anyway new) in the Terrain Editor menu called Replace. So I noticed my terrain is very thick underneath, so I wanted to delete that section to reduce lag. So I replaced all of the rocks beneath the terrain with air.
Without the rocks and excess terrain beneath it, it looks like this:

But with all of the excess, unwanted terrain beneath, it looks like this:

Since eroding the excess terrain can use up more memory (because that makes the terrain more complex), if I replace the unwanted terrain with empty air, will that reduce lag and memory usage? (I checked underneath the terrain after replacing, and it doesn’t look too complex to me.)

Thanks!

[scotch101tape]

The way terrain works is through a voxel system made up of 4x4x4 cubes. Each cube holds position and how much it “fills” the space given. A more detailed explanation is given here. With this in mind, we can safely say that less terrain is less data and less lag. This also means that eroding the terrain should not take up more data than completely removing parts as long as you fully erode the same amount of voxels.