Birdi's Volumetric Tool is designed for precise volume calculations of terrain, stockpiles, and land features. This guide explains how to use the tool, interpret the results, and choose the appropriate calculation methods.
Create a volumetric layer
Select +Add data
Select create volumetric folder
Access Volumetric Layer Toolbox.
Select the polygon from your Layer Panel to open the Volumetric Layer Toolbox.
Select the surface layer to use for the calculation, such as your Digital Elevation Model (DEM). If you have the wrong layer selected, a warning will show.
Select Calculation Method
Choose your desired calculation method:
Linear Fit: Fits a linear plane to the points within the defined polygon/annotation, best for calculating volumes when the ground beneath stockpiles is sloped or irregular.
Lowest Point : Identifies the lowest elevation point in the polygon and creates a horizontal base plane at this elevation. Suitable for flat ground beneath stockpiles.
Base area: The plan area of the polygon at the base surface.
Select the surface layer to use for the calculation, such as your Digital Elevation Model (DEM). If you have the wrong layer selected, a warning will show.
Perform the Calculation
Click Calculate to update the volume values (this may take a moment).
The following values will populate in the Volumetric Layer Toolbox:
Cut Volume: The volume of material that needs to be removed to achieve the desired grading level. Commonly involves excavation of soil or rock from higher elevations.
Fill Volume: The volume of material required to fill low-lying areas to reach the desired grade. Fill material can be sourced from cut areas (on-site) or externally.
Net Volume: Represents the overall material balance:
Net Volume = Cut Volume − Fill Volume. A negative Net Volume indicates a deficit, meaning additional material needs to be brought in.
Assign a material for tonnage
Once your volume has calculated, open the Material selector in the Volumetric Layer Toolbox.
Choose a material from the library — each option shows its density in t/m³ — or scroll to Custom… to enter your own Material name and Density (t/m³).
Material and Tonnage populate immediately alongside your volume values. No need to recalculate.
Hold Shift to select several volumes and apply the same material to all of them at once.
Leave the material unset if the volume doesn't need a weight.
Full detail: How to calculate stockpile tonnage in Birdi
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Disclaimer: The accuracy of the volumetric outputs depends on the quality and resolution of the input data and polygon boundaries. External factors, including data inconsistencies, terrain complexity, and incorrect layer assignments, may affect calculation results. Users are encouraged to validate outputs against field measurements where precision is critical.
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For more information, you can view these other helpful articles