1.Select the existing Mesh.
2.With the Mesh tool, draw a closed polygon that falls entirely within the Mesh polygon.
3.The New Mesh Points dialog box opens.
4.Choose the “Create Hole” radio button.
5.Choose an option from the drop-down menu to define the relationship between the newly created points and existing ones.
–No Surface Fitting: the slopes of the Mesh will be connected to the bottom elevation of the Mesh.
–Fit to User Ridges or Fit to All Ridges: With these options, no slopes will be connected to the bottom of the Mesh, allowing you to place your building exactly into the excavated site.