How Sheet Matching Works
Summary: Bedrock’s sheet matching uses multiple signals (sheet numbers, titles, visual similarity) to automatically pair corresponding sheets between drawing revisions without manual intervention.
The Problem
When comparing drawing revisions, you need to match sheets:
- A1.01 in the old set should compare to A1.01 in the new set
- But what if sheet numbers changed?
- What if sheets were added or removed?
- What if one discipline was renumbered entirely?
Manual matching is tedious and error-prone. Bedrock automates it.
How Bedrock Matches Sheets
Signal Analysis
Bedrock analyzes multiple signals to identify matches:
| Signal | Weight | Description |
|---|---|---|
| Sheet number | High | A1.01 matches A1.01 |
| Sheet title | Medium | ”First Floor Plan” matches similar titles |
| Visual similarity | Medium | Overall drawing content and layout |
| Title block position | Low | Location and format of title block |
No single signal is definitive. The combination provides robust matching.
Matching Process
- Extract metadata: Read sheet numbers and titles from both sets
- Direct matches: Pair sheets with identical numbers
- Title matching: For unmatched sheets, compare titles
- Visual matching: For remaining sheets, analyze visual similarity
- Confidence scoring: Assign confidence to each match
- Flag ambiguous: Highlight matches needing verification
Handling Edge Cases
| Scenario | How Bedrock Handles It |
|---|---|
| Renumbered sheets | Visual similarity + title matching |
| New sheets | Flagged as “Added in current revision” |
| Deleted sheets | Flagged as “Removed from prior revision” |
| Split sheets | Each new sheet matched to original when possible |
| Combined sheets | Original sheets matched to combined |
| Different page counts | Unmatched sheets listed separately |
Matching Accuracy
| Scenario | Typical Accuracy |
|---|---|
| Numbers unchanged | 99%+ |
| Numbers changed, titles same | 95%+ |
| Numbers and titles changed | 85-95% (may need review) |
| Completely reorganized set | Manual review recommended |
When automatic matching is uncertain, Bedrock flags the sheet for human verification.
What Sheet Matching is NOT
- Not OCR-dependent: Works even without text layer
- Not exact matching only: Handles variations in numbering
- Not foolproof: Ambiguous cases are flagged, not guessed
- Not manual pairing: Automation handles the work
Verification and Override
After automatic matching:
- Review match summary
- Check flagged uncertain matches
- Override incorrect matches if needed
- Proceed to comparison
Most comparisons require no manual intervention.
Technical Details
| Aspect | Specification |
|---|---|
| Processing per sheet | Sub-second |
| Maximum set size | 1,000+ sheets |
| Supported formats | |
| Language support | Any (visual matching is language-agnostic) |
FAQ
What if Bedrock matches the wrong sheets?
Uncertain matches are flagged for review. You can override any match before comparison runs. Incorrect matches don’t silently proceed.
Does sheet matching work across different CAD systems?
Yes. Sheet matching analyzes the output PDF, not the source format. Drawings from AutoCAD, Revit, or any other system work the same.
What about sheets with no numbers?
Bedrock falls back to title and visual similarity. Sheets without numbers or titles are flagged for manual matching.
How long does matching take?
Matching typically completes in seconds, even for large sets. It’s part of the overall comparison processing time.
Key Takeaways
- Sheet matching uses multiple signals (number, title, visual)
- Automation handles standard cases without intervention
- Edge cases (renumbering, additions, deletions) are detected
- Uncertain matches are flagged, not guessed
- Manual override available when needed
- Works across any CAD system or drawing source
Last updated: 2026-02-04