1. Create a 3D UGrid from scratch. Right-click in the Project Explorer and select New | UGrid 3D.... In the New UGrid dialog, enter the information for the X-, Y-, and Z-Dimension of the grid. 2. Create a 3D UGrid from a coverage. Right-click on the desired coverage and select the Map To | UGrid command. In the Map → UGrid dialog, set the Dimension drop-down to "3D". Enter the rest of the information for the grid, including the X-, Y-, and Z-Dimension information.