Here is a quick way of getting what you need from a huge PT cloud plus a lot more. Let’s create what I call a Hybrid PT Cloud. We'll take a huge 2500 acre LIDAR created PT cloud that is nearly 37 million points and import it into Civil 3D as PT clouds. We will do this by eventually creating three separate DWGs, each with one surface. Using data shortcuts we will reference into a third DWG the two other surfaces and paste them together to make a HYBRID surface that includes both.