You can graphically compare old and new Gerber files for a project using Altium 365’s Gerber Compare feature. This capability is beneficial when PCB designers need to confirm changes in Gerber files before fabrication (e.g., unintentional changes). When the board layout is complex or large, but the changes are small, it can be very time-consuming to identify all the differences without a comparison tool.
Tip: You can compare two Gerber files by selecting any release in Project History. This can be accessed through Releases or Project History.
Access through Releases: Select Releases on the left side of the screen, and choose one release from the list. Click the three dots in the upper right-hand corner of the selected release, and select:
- Compare Gerber to >> Fabrication A.x
Access through Project History: Select History on the left side of the screen, and choose one project already released from the list. Click the three dots in the upper right-hand corner of the project and select:
- History >> … >> Compare >> Gerber to >> Previous (Fabrication A.x)
- History >> … >> Compare >> Gerber to >> Select Release
- History >> … >> Compare >> Gerber to >> Files (This option allows the comparison of other generated Gerber files in Altium Designer that have been uploaded to Altium 365 Personal Space).
You will receive an email when performing the first run of schematic comparison; it might take some time (30 seconds or more, depending on the board's size). Consecutive runs of the same dataset are instantaneous as the data are cached. When you see this screen, you can choose to wait for the process to complete or close the page:
The email will be sent out as soon as the process is complete. After that, you can access the comparison by clicking the “Open in Altium 365” link:
Once the comparison set has been selected, the results are presented in the Gerber Compare view in a new browser tab.
The Differences panel on the left-hand side displays a view of the following sections’ details:
- The identification of each layer
- The quantity of layers
- The differences in each layer
- The x-y position of the selected group of differences
Changes organized in groups with explicit identification on the screen correspond to areas of the board that change. Changes are displayed per layer. Clicking on a group will show a compare view that highlights any differences between the two revisions. As you can see, each group has a number, which is the number of differences.
You can quickly switch between different layers and revisions on the side panel (see Fig. 6 - Details of the Differences panel). The location and zoom settings are preserved.
Move the mouse over the Compare tab to show the number of group differences.
Each detected group of differences is numbered and outlined. Click on an entry in the left-hand pane to focus on that specific difference in the main viewing area.
Select a layer and click on the group number zooms into the corresponding board area.
To measure the distance between two points, select the measure icon on the top right corner to measure and display the distance between any two points in the current document.
You can also change measurement units by clicking the information icon switching between mil and mm.