Global Mapper v26.0

Terrain flattening

Hi guys. I am attempting to remove some unwanted artifacts on the surface within a DEM before comparing to a previous survey. I am using the area feature but have only been able to get it to work properly when using a square or rectangle area. When drawing a free form polygon with multiple vertices it will always remove that area feature from the surrounding surface. I just want to remove the item and blend the resulting arbritrary surface in to the align nicely with the ground height where the vertices are before creating a 3D TIN Mesh, running comparisons. Thank you.