Difference between volume and area from DEM and MEsh

[wizprod]

Hi!

I have an issue where a stockpile will have different volumes and areas depending on its processing-origin.

From Mesh:
- Area: 5158 m2
- Volume: 7139.9 m3

From DEM:
- Area: 2307.9 m2
- Volume: 7271.9

I suspect that the area reported by the Mesh is a total surface area, also on the buttom side ?
But given that the outline is more or less the same, why is there a 132 m3 difference between the 2 methods ?

[Alexey Pasumansky]

Hello wizprod,

Yes, mesh based calculations are providing the area value as a sum of areas for each polygon of the model. DEM-based area measurement gives you 2D area estimation.

The volume calculation of the mesh includes the total volume inside the watertight mesh components. If you are using Close Holes option for making holeless mesh model, which has limited (practically no) control, the based plane cannot be confirmed, like it can be done for DEM based measurements.

[wizprod]

Hello wizprod,

Yes, mesh based calculations are providing the area value as a sum of areas for each polygon of the model. DEM-based area measurement gives you 2D area estimation.

Thanks! So the trick to only have it show the correct surface area is to not close the holes, and hence not closing the "ground"?

the based plane cannot be confirmed, like it can be done for DEM based measurements.

So for the volume, the correct/most trustworthy way to do it is through the DEM ?


Is there a way I can re-use the polygon shape from the DEM on the Mesh, so the outlines are exactly the same ?
I use the surface-area for error-estimation calculations.