Calculating As Built Volumes
Updated November 30, 2017
This article applies to:
- RoadEng Civil
- RoadEng Forestry
In the Location module, cross section end areas (and therefore volumes) are calculated using a layer merging process which simulates the construction sequence. With fixed cross sections, you control the shape and order of the layers so it is important to understand this process.
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Layer 2 is compared with layer 1 (usually topo) and the difference is calculated; this defines the cut and fill areas for layer 2 (in this case stripping).
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Layers 1 and 2 are merged to create a new merged surface (in this case the stripped surface).
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The merged surface replaces layer 1, layer 3 replaces layer 2 and the two steps above are repeated.
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Repeat until all layers are processed.
The figure below shows the progression of the merged surface.
| Fixed cross-section |
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|---|---|
| Merged surface after Stripping is applied |
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| Merged surface after sub-cut is applied |
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| Merged surface after final is applied |
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Figure 1: Depiction of Merged Surface Progression
Note: The order of the layers in the Section Editor Tree-control is very important. Cut fill volumes are calculated between the current layer and the merged surface.