Overlays let you compare two pages by layering one on top of the other. Use them to track changes between revisions, coordinate across disciplines, or check as-built conditions against design documents.
Opening the Overlays popover
Click the Overlays button in the toolbar at the bottom of the canvas, next to the zoom controls. The popover shows existing overlays for the current page. If none exist, you will see an empty state with a New overlay button.
Creating an overlay
Click New overlay (or New if overlays already exist). A drawer opens showing all pages in your project. Select the page you want to overlay on top of your current page and the alignment interface appears.
Aligning pages
After selecting a comparison page, the overlay appears on the canvas with adjustable positioning. Drag the overlay to align it with the base page, matching reference points like corners, gridlines, or title blocks. Use corner handles to resize the overlay if the pages are at different scales. Use arrow keys for fine adjustments, or hold Shift for larger steps.
Adjust the Opacity slider to control transparency while aligning. Click Compare when alignment is complete.
Viewing comparisons
Completed comparisons appear listed in the Overlays popover. Click any comparison to activate it. The overlay renders with a color-coded legend:
Color | Meaning |
Black | Unchanged |
Blue | Added |
Red | Removed |
Click the eye icon next to an active comparison to toggle visibility without losing the comparison data.
Common use cases
Revision tracking: Compare different versions of the same sheet to identify changes. Upload both revision versions as separate pages and create an overlay between them.
Discipline coordination: Layer different trade drawings to check for conflicts between landscape, irrigation, and grading plans.
As-built comparison: Compare completed work to original plans. Add the as-built drawing or site photo as a page in the project, then overlay it on the design document.
Managing overlays
You can create multiple overlays for a single page to compare against different revisions or trade drawings. Switch between comparisons by clicking different items in the Overlays list, which shows your five most recent comparisons for the page.