Too big area for 2.5D volume calculation

[pttpx2]

Hi,

I have following data:
1. input terrain model (before earthworks - points with XYZ coordinates)
2. current terrain model (pointcloud measured with a drone)

I need to calculate added and removed volume values for the whole terrain in order to show progress of the earthworks.

As you can see on pictures 1.jpg and 2.jpg I clipped both models to exactly the same range.

Then I used 2.5D volume calculation tool to compute added and removed volume. I chose "interpolate" method for empty cells. You can see all settings in settings.jpg. It does calculate volume but output height difference raster's area is a bit bigger then input and current terrain models'. In 3.jpg you can see the output height raster and in comparison.jpg you I marked in red circles areas that are unnecessary. I think it computes a little to much volume because of those unnecessary areas. I know that I could change "interpolate" to "leave empty" method for empty cells and there will be no unnecessary areas but in such case it will cause loss of volume inside of the terrain model.

How can I calculate volume only for extents shown e.g. in 1.jpg but with interpolating empty cells inside the area?

[daniel]

You would have to do the 'interpolation' work manually, before using the 2.5D Volume Calculation tool:
- use the Edit > Mesh > Delaunay 2.5D triangulation tool to create a mesh
- sample a lot of points on this mesh
- segment the parts that you don't want with the scissors tool
- use this dense cloud for volume calculation, without interpolation