Step 7B: Data

Purpose

This sub-stage is the read-only measurement review for Step 7. Once the naming, grouping, and pairing logic from Step 7A has been set, the app presents the rib and boss results as a structured dataset that can be checked, compared, and exported before the final analysis in Step 8.

What is calculated

Each rib or rib group is summarised through the following metrics:

Measurement Description
Arc radius Radius of the best-fit circular arc, when the rib is not effectively straight
Length Measured length of the rib trace or grouped rib system
Impost distance Height difference between the rib's fitted arc centre and the chosen impost line
Span Horizontal measure derived primarily from boss/apex logic and rib pairings; an experimental semicircular mode is also available
Apex height Height above impost line derived primarily from rib pairings; an experimental semicircular mode can also supply it for flagged groups
Fit error Residual error of the arc fit, used as a quality check

Boss stones are also summarised, including their height above the impost line when enough apex information is available.

The measurement tiles can show different states depending on the rib geometry. The example below shows the expected values for one regular curved rib and one straight rib, where some arc-based measurements become unavailable or not applicable.

Step 7B possible measurement values for two ribs: one regular curved rib and one straight rib, illustrating how the metric tiles change depending on rib geometry.

Workflow

Step 7B Data interface: full-page layout with the 3D viewer, rib measurement list, detail panels, boss-stone panel, and arrows highlighting the main areas used during review.

1. Review the measurement list

  • The Rib Measurements panel shows all current display rows: single ribs, auto-detected groups, and manual groups.
  • Multi-rib groups can be expanded to inspect their component traces.
  • Click a row to inspect its detailed metrics.

2. Use the 3D viewer to verify the geometry

  • Error Heat colours the rib by point-wise distance from the fitted arc. Use it to spot poor fits or local distortions.
  • Best Fit Arc replaces the heatmap with the fitted arc geometry itself.
  • Click ribs or boss labels in the viewer to jump to the corresponding details in the side panels.

3. Inspect the selected metrics

  • The details card reports the main measurement tiles for the selected rib or group.
  • A grouped selection also lists the relevant apex/boss information and the individual ribs it contains.
  • Straight ribs may show some measurements as not applicable rather than numeric.
  • Ribs without a valid pairing may show Apex Height as unavailable.

4. Review boss-stone heights

  • The Boss Stones panel shows the current height above impost for each boss where an apex can be resolved.
  • Heights may come from explicit rib pairings first, with boss 3D height (lowest point) data used as a fallback.

5. Export the data if required

  • Export Ribs writes the rib or rib-group table to CSV.
  • Export Bosses writes the boss-stone height table to CSV.

6. Continue to Step 8

  • Clicking Continue to Analysis saves a Step 7B summary snapshot for the final analysis page.

What to look for

  • groups that still combine the wrong traces
  • unusually high fit errors compared with the rest of the vault
  • missing apex heights caused by absent or incorrect pairings
  • implausible boss heights caused by a poor impost line choice

If the measurements do not look credible, return to Step 7A and revise the naming, grouping, pairings, or impost setup before exporting or proceeding.

Click Continue to Analysis to proceed to Step 8.