Area (surface) by volume

I would like to create area based on volume (just like NavmeshCut works to mark cutting). I don’t want to use separated object (with RecastMeshObj) to scan it to create seams. I just want to tell the navmesh generator to divide triangles into the areas based on the current mesh/collider not on a new mesh.
What’s the point? If I have e.g. irregular terrain mesh there is no way to create a proper area when scan the graph. Ok it’s feasible but requires additionally mesh extracted from the main mesh that will cover the area. On flat surface also is an issue. I have to put RecastMeshObj just a little bit over the ground and if it’s too high it can create slope. In other hand if it’s too low will be covered by ground and ignored.
Is there a way to handle it somehow?

Hi

I don’t quite understand what you are trying to do.
Does a navmesh cut with the isDual setting enabled work for you?

Hi!
It does. Thank you!