Hi Janderson,
Sorry you've been having trouble getting your use-case to work. I'm not exactly certain of your workflow so figured I would put together a few videos to show the main points.
The way it works:
- It calculates the volume between the [plane you move up and down] and [an elevation surface]
- The surface needs to be the current terrain situation
- The plane is where you want to surface to be after the change
- It doesn't have to be horizontal
Fake scenario - taking out dirt to build a bridge over a waterway
Video 1 - interactive creation
- Activate the tool, use the Polygon option, choose the 'Ground' elevation surface
- Which is using a local elevation raster (tif file) in the area-of-interest
- Click on the ground surface to digitize in the cut shape
- The first click sets the elevation for all the other vertices (ie: it is flat / horizontal)
- Drag it up/down - the 'Cut' value is the only one that matters
Video 2 - using a polygon feature (in the 2D draped category)
- Activate the tool, use the From Layer option, choose the 'Ground' elevation surface
- Set the polygon layer name - ie: 'Test_CutFill'
- Note - I've already selected the polygon feature (and it is 'draped' on the ground surface)
- The polygon centroid sets the elevation for all the other vertices (ie: it is flat / horizontal)
- Drag it up/down - the 'Cut' value is the only one that matters
Video 3 - using a polygon feature (in the 3D vector category)
- Move the polygon layer into the 3D (vector) category
- Note - the polygon has its own z-values
- Use the Layer option again (same parameters - 'Ground' elevation surface and 'Test_CutFill' layer)
- Note - the polygon feature is still selected
- The polygon's z-values set the elevation (we want it to be planar, but it doesn't have to be flat)
- Video 4 shows a planar-but-tilted 3D polygon
- Drag it up/down - the 'Cut' value is the only one that matters
My guess at your issue is that you're not referencing an elevation surface (as the base terrain) in the expected manner, but it's hard to be sure. Hopefully the videos help.
Thanks!
-Nathan