In two previous videos I explained the process of importing a LiDAR point cloud into Recap and processing it out as an RCP or an RCS file for use in Civil 3D. Then I explained how to import that RCP or RCS file into Civil 3D. If you have not yet seen those videos you can find them here: Point Cloud to Recap to Civil 3D Workflow.
Now that we have the data in Civil 3D we need to generate a surface representing the existing ground conditions. The problem we have though is that the point cloud imports everything that is scanned. This means I will get contours representing tops of trees, power poles, signs, fire hydrants, vehicles, etc. I only need to show a surface which contains ground shots. In this video I explain the process of filtering out just the ground data and then creating a surface from that data: