Tools > Import / Export Mechanical Layers

Tools > Import / Export Mechanical Layers

Includes Layer Pairs

That's it !

PCB - Component Layer Pairs

View Configuration > Right click > Add Component Layer Pair

Click on image to view

As shown above I prefer to display the Mechanical Layer numbers in my component layer pairs. This involves creating, then editing the pair and selecting N/A for the Layer Type.

That's it !

Script - MechanicalReMapper.pas v1.04 - Altium Discussion Forums

Script - MechanicalReMapper.pas v1.04 - Altium Discussion Forums: 

"This version has a known bug with the PCB Layer Pairs. So if you have them in a PCB, check that they are still correct after running the script. No other bugs are known."

'via Blog this'

Setup and Using layer pairs - YouTube

Setup and Using layer pairs - YouTube By Microdex:

This video includes creating a Layer Pair for Assembly Drawings that use '.designator' on a mechanical layer.

Key points include defining the Layer Pairs while all placed parts are on the Top Layer.

Reduce Component Clutter

Using Layer Pairs and Board Layer Sets can reduce component screen clutter for double sided board designs and simplify your library components.

Double-sided board screen clutter caused by overlapping component outlines and courtyards.

Solution: Create Layer Paired views for Top only, Bottom. When you flip components from one side of the board to the other, paired mechanical layers are flipped to the other mechanical layer in the layer pair.

First define two Layer Pairs. Note the color scheme for Top (Red) and Bottom (Blue) Layers.

Layers 4 and 8 are paired; layers 15 and 25 are paired. The library parts in this example are using layers 4 and 15 for component outlines and courtyards. The component outlines are on layer 4 and the courtyards are on layer 15. Your Layer Pairs will likely be different than those shown and will depend on the layers you chose for your PCB Library *.PcbLib files.

Layers 4 and 8 are the paired component outline layers with both layers set to color gold. Layers 15 and 25 are paired courtyard layers with both layers set to color green. Again your colors may be different, depending on your preferences.

When using the same colors on the layered pairs we will see familiar color schemes for the outlines and courtyards in all three of the Board Layer Set views.

After defining the mechanical layer pairs for outline and courtyard layers and setting the paired layer colors, we need to define three Board Layer Sets. Defining Board Layer Sets will allow us to enable and disable views for top or bottom component outlines and courtyards.

Create three new Board Layer Sets:

Top Layers

Bottom Layers

Top and Bottom

The Top Layer Set includes the Top Layer and the component outline and courtyard layers as defined in the PCB Library.

The Bottom Layer Set includes the Bottom Layer and the paired layers for component outlines and courtyards.

The Top and Bottom Layer Set includes all of the settings from both the Top and Bottom sets.

Ok, let's take a look at these three layer sets.

Top layer along with the Component Outline and Courtyard can be displayed.

Bottom Layer along with the Component Outline and Courtyard can be displayed.

Top and Bottom Layers.

Notes:

You cannot define layer pairs in the PCB Library Editor; this feature is only available in the PCB Editor.

The Board Layer Sets and Layer Pair settings are stored in the *.PcbDoc file, they are not saved in preferences.

For more, see this You Tube video by Microdex