The overlay feature lets you compare different pages or plan revisions by layering them on top of each other. This is useful for tracking changes between revisions, coordinating across disciplines, or comparing as-built conditions to design documents.

Click the Overlays button in the left canvas toolbar. The popover shows existing overlays for the current page. If none exist, you will see an empty state with a New overlay button.

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.

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.

Completed comparisons appear listed in the Overlays popover. Click any comparison to activate it. The overlay renders with a color-coded legend:

Click the eye icon next to an active comparison to toggle visibility without losing the comparison data.

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 by overlaying site photos or as-built drawings on design documents.

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.