I have a large point cloud attached to my file that has point shots for everything on the same classification. Therefore, I cannot turn off everything besides the ground shots to create a terrain surface for the existing ground of my project area. When I try to create a terrain from point cloud, it fails to import and gives the error message that "Terrain state is invalid - Terrain MUST be valid and triangulated for this tool." I have attached an image that shows the point cloud and the properties of it that show the classifications. How can I work around this error to create a terrain surface of the ground excluding the trees, poles, etc?