Split Nonterrain Surface
Divide one surface group into two separate groups, cut by mask.
Apply to control geometry, not terrain. This is useful to divvy up e.g. a flat material zone control group inte several smaller ones.
Type: PrepMenu: Extensions > Landshape > Prop > Split Nonterrain Surface
First, Select a non-terrain surface, and Select a mask. Then run Split Nonterrain Surface.
An Example
For instance, you can first run Clone Zone to extract a 2D terrain material representation. Then, you can create a mask goup. Then, select both the zone clone group and the mask group.