Choose two revisions
Select the original drawing and the newer revision you need to review.
Drawing revision comparison
How to Compare DWG and PDF Drawing Revisions on Windows
Overlay two drawing revisions and make added, removed and unchanged content easier to identify—without switching repeatedly between separate windows.
Local Windows software · No drawing uploads · Perpetual license
DWG and PDFReview common drawing formats
Color overlaySee where revisions differ
Local processingKeep drawings on your PC
Save the resultDocument and share findings
Why visual comparison?
Small drawing changes can be surprisingly difficult to find
Moving back and forth between two revisions makes it easy to overlook a changed dimension, removed symbol, revised note or small geometry adjustment. Drawing comparison places the revisions together and uses contrasting colors to reveal areas that deserve attention.
Overlay the drawings
ViewCompanion renders the files together using separate comparison colors.
Inspect the changes
Zoom into changed areas and save or print the comparison for documentation.
Step-by-step
A more reliable revision-review workflow
The comparison does not decide whether a design change is correct. It helps the reviewer find the areas that require professional attention.
- Open the original drawingLoad the earlier DWG, PDF or other supported drawing file.
- Start drawing comparisonSelect the comparison command and choose the revised file.
- Select comparison colorsUse distinct colors for original and revised content.
- Create the overlayView both revisions together in the same drawing area.
- Review highlighted areasInspect dimensions, notes, symbols, linework and title blocks.
- Add review notesUse annotations to record observations when needed.
- Save or print the resultCreate a record that can be shared with colleagues or customers.
DWG and technical PDF
Drawing comparison is different from text comparison
Ordinary PDF comparison tools often focus on changed words. Engineering drawings communicate through geometry, linework, dimensions, symbols and placement. A visual overlay can expose graphical changes that a text-only comparison would never report.
ViewCompanion Premium is designed for technical documents and can also be used to view, annotate, measure, print and convert drawing files.
Common comparison challenges
- Different scale
- The revisions may not align correctly.
- Different position
- Drawing content may have shifted on the page.
- Missing resources
- Fonts or referenced files may affect appearance.
- Rasterized PDF
- Scanned pages behave differently from vector drawings.
Planned feature
Synchronized side-by-side drawing review
A planned ViewCompanion feature will let you open an old and new revision beside each other. Zoom or pan the master view, and the second view will follow automatically—useful when you want to inspect both original drawings without an overlay.
Questions and answers
Drawing comparison FAQ
Can ViewCompanion compare DWG drawing revisions?
Yes. ViewCompanion Premium can open DWG files and create a visual comparison that helps reveal differences between revisions.
Can I compare technical PDF drawings?
Yes. PDF drawing revisions can be overlaid for visual comparison, which is useful for graphical content that ordinary text comparison may miss.
Does comparison automatically approve or reject changes?
No. It is a visual review aid. The user must still assess whether each detected difference is intentional and correct.
Are my drawings uploaded to a server?
No. ViewCompanion Premium is Windows desktop software and processes drawing files locally.
ViewCompanion Premium
Try drawing comparison with your own revisions
Download the free trial and explore DWG and PDF viewing, comparison, annotation, measurement and conversion.
