Volume Calculation using Autodesk Land Desktop

[mobarez]

To evaluate the cutting volume of existing ground to reach a flat surface with specified elevation We have point database includes 30 points X,Y, and Z gathered from existing ground.
Using Autodesk Land Desktop 2009, I have defined surface1 (associated to existing ground) with those 30 points, and surface2 (associated to existing ground) with just 4 points with the specified elevation. but I can not get the reasonable result. Is it because of the difference between number of points used to define surfaces or is there a better way to define surface2(final ground with specified elevation), I have tried both grid volumes and composite volume methods.

 

[hydroponder]

The number of points should not make a difference, especially if the final surface is flat. You may want to import the 3D lines and check to see if your surface is indeed correct. To do this, go to Terrain -> Edit Surface -> Import 3D Lines. Do this for each surface and check to make sure the elevations associated with the surface make sense. Another thing to check: when you calculate volumes with Land Desktop, it usually creates a surface associated with the cut/fill. Create contours using this surface and you will be able to see where your error resides. Maybe you have an errant point in the existing ground. You can also look at the Surface Statistics and make sure your maximum and minimum elevations make sense. You should probably do this first as it is the easiest.