Quick answer: Open the drawing in the Document Register, click Compare, select the second revision from the dropdown, and click Compare again. The overlay highlights differences in red and blue, with shared elements shown in black.


The two revisions will appear overlaid on screen using a colour-coded system:
This makes it easy to spot exactly what has changed, been added, or removed between the two versions.
Problem: The Compare option is not available for a document
Cause: The comparison feature only works with PDF documents — other file types are not supported
Fix: Ensure the drawing is uploaded and stored as a PDF before attempting to compare revisions
Problem: Only one revision appears in the dropdown
Cause: The drawing has not yet had more than one revision uploaded to the register
Fix: Upload an additional revision to the document before using the compare feature
To share the comparison with others:
Revision comparison, drawing diff, compare drawing versions, overlay revisions, PDF revision overlay, document version comparison, compare PDF drawings, drawing change tracking