Altium Designer Documentation

Choose Documents To Compare

Created: January 12, 2023 | Updated: January 12, 2023
Applies to Altium Designer version: 21

The Choose Documents To Compare dialog, shown in basic (left) and advanced (right) modes.   The Choose Documents To Compare dialog, shown in basic (left) and advanced (right) modes.The Choose Documents To Compare dialog, shown in basic (left) and advanced (right) modes.


The Choose Documents To Compare dialog provides controls to choose which documents to compare when using the Comparator with any detected differences presented in the subsequent Differences between dialog. It is available in two modes - a basic mode that allows you to quickly select the target PCB document to compare against the project's source document hierarchy, and an advanced mode that gives control over the documents compared (document-to-document, project-to-project, or document-to-project).


The dialog is accessed in the following ways:

  • Right-clicking in the Projects panel then choosing the Show Differences command from the context menu.
For use in basic mode, ensure the project of interest is currently focused in the panel.
  • Click Project » Show Physical Differences from the main menus.


  • Documents list - this main region of the dialog lists the documents that can, and selectively are, to be compared. The appearance depends on the mode as determined by the Advanced Mode option:
    • Basic Mode - a single list will present the PCB documents for the focused design project. Choose the specific PCB document to compare against the design hierarchy of that project.
    • Advanced Mode - two lists are presented, each displaying the currently open projects and their documents. Choose a document on the left to compare with a document on the right. You can choose to compare a document with another document, a project with another project, or a document with a project (as per basic mode).
  • Advanced - use this option to toggle the dialog between its basic mode (disabled) and its advanced mode (enabled).
After choosing the documents then clicking OK, the Comparator will perform the comparison. The Comparator will adhere to the setup defined for it on the Comparator tab of the Project Options dialog and, if any differences are detected whose associated comparison types are not set to be ignored, those differences will appear in the Differences between dialog.
Found an issue with this document? Highlight the area, then use Ctrl+Enter to report it.

Contact Us

Contact our corporate or local offices directly.

We're sorry to hear the article wasn't helpful to you.
Could you take a moment to tell us why?
200 characters remaining
You are reporting an issue with the following selected text
and/or image within the active document: