Hey, thanks for reply!
I tried the RecastMeshObj but it appears it is only half-working. Perhaps there is a setting I’m missing.
Here’s a simple example of what’s happening.

In this image, I have a Unity terrain and a cube that is to act as the nav mesh occluder.
The cube is not on a layer that the nav mesh uses and contains a recastMeshObj component with an area set to -1.
When I bake the graph, it does indeed appear to cut out the mesh now, which is great, but it only cuts out the edges. To be clear, the pink nav geometry is NOT on the cube itself, it is on the terrain below it. (It’s a flat piece of terrain for simplicity sake)
I tested this with a chunk of mountains as well, and the large encompassing cube causes the edges around it to be cut out, but the mountains themselves inside of the cube still have nav mesh geometry on them.

As you can see from the image, the base of this large cube has a cut around its edges, but the mountains inside of it still contain a nav mesh.
Thanks for the help!