Hi.
If we import a LandXML surface and then we want just a portion of the surface, generally I apply a outside boundary from a polyline that I draw.
The issue is that polyline is in some segment outside of the boundary of that surface then Civil 3D creates TIN triangles.
Civil 3D should remove them and not trying to generate invented surface outside the existing boundary of the surface.
Civil 3D should create a final boundary using substract between both boundaries (the existing boundary and my proposed boundary).
