How do I compare two revisions of the same drawing?

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.

This feature is only available on PDF Documents

Interactive Demo

"For the best experience, hover over the bottom right corner of the demo to enable fullscreen."

Steps

What to expect

The two revisions will appear overlaid on screen using a colour-coded system:

• 🔴 Red — content from the first (newer) revision
• 🔵 Blue — content from the second (older) revision
• ⚫ Black — elements common to both revisions

This makes it easy to spot exactly what has changed, been added, or removed between the two versions.

Common issues

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

Sending the comparison by email

To share the comparison with others:

1. Select Attach Comparison from within the comparison view
2. A new email window will open with the comparison already attached
3. Compose your message and send as normal

Related

• How to upload a new revision to a drawing
• How to send a document transmittal

Also known as

Revision comparison, drawing diff, compare drawing versions, overlay revisions, PDF revision overlay, document version comparison, compare PDF drawings, drawing change tracking