When combining survey (tight accuracy) with GIS (less accuracy), you can get false near vertical faces at the edges of the survey data. I usually left a buffer of between 10 and 25 feet around the survey data to let the surfaces create a smoother transition between the two surfaces. This can be done by drawing the hull/perimeter of the survey surface into a 2D file and then using the move parallel command to create the buffer limit. Then I use that to create a void area in the original data. Then, when you combine them, if the void is not automatically cleared, you can clear it manually.
As a brute force approach, I use the shape to create a fence and use the DTM tools to fence delete that surface data within the shape.
It is critical that the edges of the survey do not end up cutting triangle legs of the original surface, leaving new points at the cut location. Those points do not really exist and and need to be avoided.
As a brute force approach, I use the shape to create a fence and use the DTM tools to fence delete that surface data within the shape.
It is critical that the edges of the survey do not end up cutting triangle legs of the original surface, leaving new points at the cut location. Those points do not really exist and and need to be avoided.