P: (Masking) Use previous masks as objects for add/subtract

or ai improvement to track an object or all the objects in the image so it can track and synch that object that was masked across multiple images where the object mask might change slightly or a lot based on the angle 

On my Mac, I can hold down the Option key (not sure what the Windows key is) and copy parts of a mask to another mask by dragging. 

For example, if I have…

Mask 2
--Brush 2
--Brush 1
--Subject 1

And…

Mask 1
--Brush 1
--Subject 1

...I can hold down the Option key and drag Brush 2 from Mask 2 to Mask 1 and LrC will create a copy of Brush 2 on Mask 1. I can then right-click on the copied Brush 2 and use Invert, Convert to Add, or Convert to Subtract (depending on its original state and what I need to do). Holding down the Option key and dragging can also be used to create a new mask from part of another mask by dragging the mask element on top of the “Create a new mask” button -- then choosing Invert to invert what the mask covers. 

I just signed in to make this very request. Often I’ve labored over the details on a subject mask, then I want subtract that from the sky or background so my sky/background processing doesn’t affect my subject.

The add/subtract mask is an amazing tool for adjusting automated mask results. The ability to add/subtract an existing mask would take this to the next level.

I’m a little surprised that this is already 2 years old. Hopefully posting here will bump it to the top of the feed.

Yes… if you construct a complex mask and then start a new basic mask (any in the “create new mask” list), you often want to add or subtract the previously-created mask to/from it. Obvious extension of current functionality. All of the masks you have created in the current photo need to be available in the list from the add or subtract button.