How to short two different Nets - create a Net Tie

This article covers the basics for the creation of a Net Tie

Starting in Version: 18.0
Up to Version: Current

Solution Details

In order to short two different Nets in the design, you will need to create a Net Tie.

• Place two pads in a footprint (PCB library)
• Short them with a Copper Region in between.
• Make sure that the copper Region just extends to the sides of the pad but not to the snap point in the middle of the pad itself. Otherwise, connecting tracks won't connect to the snap point of the pads later in the design.

Use Tools ► Footprint Properties to give it a Name and to set the Footprint Type to one of the Net Tie options.

You will also need to create a Schematic Symbol in a Schematic Library and use the Properties panel to set the symbol Type to one of the Net Tie options.

​​
​​​​​(Don't forget to add the footprint to the schematic library symbol.)
https://www.altium.com/documentation/altium-designer/a-look-at-creating-library-components-ad

If you see the error message:
Net Tie failed verification: [...] has isolated copper, then the shorting copper in between the Net Tie is too small, and is not connecting the Pads.
 

For further information and reading, review the following resources:

https://resources.altium.com/p/using-net-ties-to-meet-pcb-design-requirements

https://www.altium.com/documentation/altium-designer/creating-connectivity-ad#intentionally-connecting-two-nets
 
https://www.altium.com/documentation/altium-designer/interactive-routing-ad#!connecting-two-nets-with-a-net-tie-component

Here's an older document, but it may have useful information:
https://resources.altium.com/sites/default/files/uberflip_docs/file_1176.pdf

You might also want to do a little research on Zero-Ohm Resistors.