# Mass Table

The Mass Table dialog displays the computed area and volume results for a volume definition across all cross-sections in a tunnel alignment. It is the primary output for quantity estimation and material tracking.

## Opening the Mass Table

Open the Mass Table in one of two ways:

- From the Volume Definition Editor, click **Calculate All** or **Mass Table**.
- From the project tree, right-click a volume definition and choose **Mass Table**.

## Grid layout

The grid columns depend on the computation method configured in the volume definition.

### Applicable Length method

| Column | Description |
|---|---|
| Section | Section name (with `*` suffix if warnings occurred during evaluation) |
| Station | Chainage along the alignment |
| Area (m2) | Computed area at this section |
| Appl. L. (m) | Applicable length -- the chainage interval this section represents |
| Volume (m3) | Area multiplied by applicable length |
| Cumulative (m3) | Running total of volume from the first section |

The applicable length for each section is computed as:

- **First section:** half the distance to the next section
- **Last section:** half the distance from the previous section
- **Middle sections:** half the distance between the previous and next sections

This ensures that each section's influence zone covers exactly the chainage interval it represents, with no gaps or overlaps.

### Average Areas method

| Column | Description |
|---|---|
| From | Name of the first section in the pair |
| To | Name of the second section in the pair |
| Sta From | Station of the first section |
| Sta To | Station of the second section |
| Avg Area (m2) | Average of the two sections' areas |
| Distance (m) | Chainage difference between sections |
| Volume (m3) | Average area multiplied by distance |
| Cumulative (m3) | Running total of volume |

The Average Areas method computes volume for each pair of adjacent sections:

```
Volume = (Area_i + Area_{i+1}) / 2 * (Station_{i+1} - Station_i)
```

This method is generally more accurate when the tunnel profile varies significantly between stations, as it accounts for the change in area by averaging.

```{figure} ../_static/images/volume_methods.svg
:width: 800px
:align: center

Comparison of Applicable Length (left) and Average Areas (right) volume computation methods across three sections.
```

## Choosing a method

```{tip}
**Average Areas** is recommended for most tunnel monitoring workflows, especially when sections are unevenly spaced or the profile changes rapidly. **Applicable Length** is simpler and sufficient when sections are closely and regularly spaced.
```

The computation method is set per volume definition in the {doc}`volume-editor`. You can change the method and recalculate without modifying the formula terms.

## Station range

By default, the Mass Table computes volumes across all sections in the alignment. To restrict the range:

1. Select the **Range** radio button in the Station Range group.
2. Enter the **From** and **To** station values.
3. Click **Recalculate** to update the grid.

Only sections whose station falls within the specified range (inclusive) are included in the computation.

## Total row

The last row in the grid shows the **TOTAL** cumulative volume across all computed sections. This is the primary quantity output for the volume definition.

## Navigation

Double-click any row in the grid to navigate directly to that cross-section on the section canvas. This is useful for inspecting sections with unusually large or small area values, or sections flagged with warnings.

## Warnings

Sections marked with an asterisk (`*`) after their name encountered evaluation warnings -- typically a missing line definition at that station. The area value for such sections may be zero or incomplete. Review these sections to ensure all required line data is present.

## Export

### CSV export

Click **Export CSV** to save the mass table as a semicolon-delimited CSV file. The exported file contains the same columns and data as the grid, including the header row and total row.

### Excel export

Click **Export XLS** to save the mass table as an XLSX file (Excel format). The export uses fpspreadsheet and produces a properly formatted workbook with:

- Bold header row
- Numeric cells for station, area, and volume values (enabling further calculations in Excel)
- Text cells for section names

```{note}
The Excel export produces `.xlsx` format (Office Open XML). Older `.xls` format is not supported.
```

### Export to PDF

**Export to PDF.** Click **Export PDF...** on the Mass Table dialog (next to Export XLS) to save a printable mass-table report. The PDF starts with a title block (volume name, tunnel, method, station range, generated timestamp + colour swatch) followed by the same grid you see on screen, paginated as needed and topped with a TOTAL row. The final page draws two stacked panels sharing the station X axis: Area (m2) on top, Cumulative Volume (m3) below. The default filename is `<TunnelName>_MassTable_<volume-definition>.pdf`. Sections that flagged warnings during volume calculation appear with a `*` next to the section name and a footnote at the table tail explains the marker.