A grid volume surface is a difference grid surface based on user-specified base and comparison surfaces as well as grid spacing and orientation.
A grid volume surface is an approximation of the difference between the base and comparison surfaces. It is formed by making a grid from points whose Z values are the differences between the Z values of the comparison and base surfaces. Therefore, the grid volume surface gives the exact difference only at the grid points. This is true whether the comparison and base surfaces are both grid surfaces, both Triangulation surfaces, or one of each.
Grid volume surfaces enable you to generate a volume quickly, which is useful for iterative site design.
A volume surface is a persistent surface object. Therefore, you can display cut and fill contours, cut and fill points, and add labels to it. View a volume property (cut, fill, net) of a volume surface by selecting Surface Properties. For more information, see To Edit and View the Surface Definition.