Object Mask Tracking Data

Unable to use the magic mask feature without tracking data disappearing after basic parameter adjustments and node editing. Seems like such a powerful feature. Would love to be able to utilize it without having to re-track so frequently. Are there plans to fix this? Or perhaps I have one of the settings wrong? Also, would love to use the magic mask to make a general selection and crop with it so as to make composites and whatnot. Thanks in advance.

I'm having similar problems using it, I'd like the ability to "freeze" the selection the same as you can do in After Effects, I'd love to use magic mask but every time I make a change somewhere in the node tree it disappears and I have to track it again. I often use this mask to select a subject, then invert it on other nodes to change elements of the background, so when the mask goes, so do all my other nodes. It's a really good tool but only useful on the most basic node structure. Unless I'm missing something too!

You're missing something...

Create a second node directly from the source node so that you basically have source -> node 1 and source -> node 2

Use node2 to create your magic / object mask and then take the blue output of node 2 and plug it into the blue input of node 1 - do your color grading, etc. on node 1 (or add a serial to node 1 -> node 3 and do your colouring there as long as you connect the blue from node 1 to node 3).

I'm sorry if my description is a bit convoluted. What you are trying to do is to eliminate upstream changes to the object mask tracker by isolating it early on in the node graph and then connecting its result forward (downstream) to the first color grading node that actually needs to know about the mask.

OK - now that's making a bit more sense, and certainly it's not asking me to re track all the time.

Thank you - I'm going to give it another try now, here's a screenshot of a node tree using this principle, I guess you could combine the image feed in a parallel node but I don't think you would need to.

Screenshot 2022-08-07 232336.jpg (50.82 KiB) Viewed 1797 times

Awesome!

I have 3 separate magic masks here. Sky, foreground, and glyph. Would I need like 9 corrector nodes for a similar setup as Ashcam? What would be the simplest way to rock this? Also, if it looks like I have no idea what I'm doing, it's because I have absolutely no idea what I'm doing but at least I'm enjoying the process. Thanks so much for responding. You're giving me hope.

I'm no expert either but my guess is that you would need one magic mask node per object you wanted to track combined with at least one other 'corrector' node to take it through to the parallel node. So you would need at least six plus the parallel node, and then your deflicker and OFX nodes.

So in short, yes, nine nodes to perform what you have illustrated. I just gave this a quick try while responding to this thread and it seems to work as expected.

Like this? It lost tracking data at some point while setting it up. I don't understand the purpose of all these extra nodes.

You might've over-complicated that a bit Brian, it's difficult to say as I don't really know what you're going for, but I believe the basic workflow recommendation being suggested here is to separate your (multiple) Object Masks from anything that could potentially invalidate those mask... so, put the masks upstream of other corrections and keep those masks separate from the corrections themselves.

Here's an example where I have three masks, each mask feeds its key into a separate corrector node where I apply the isolated correction as needed:

Screenshot 2022-08-12 at 10.01.40.jpg (132.53 KiB) Viewed 1497 times

Mask 1 is an Object Mask of the man on the mat, with Corrector 1 using that mask to turn him green.
Mask 2 is an Object Mask of the mat, with Corrector 2 desaturating that mat.
Mask 3 is an Object Mask of a book (on the mat), with Corrector 3 turning it red.
The final corrector is an OFX 'Glow' filter applied globally across the scene.


Here's a version where I've added a primary corrector that neutralises the warmth in the original shot... note that the Object Masks are not affected. It doesn't matter that I introduced this correction after processing those original object masks, as this new correction doesn't affect anything that is feeding the mask ie the masks are still coming from the original unaffected shot, for them, nothing has changed:

Added Primary.jpg (190.58 KiB) Viewed 1472 times

And heres a crazy version where I've used the primary corrector to apply a wild horizontal blur to the image, superimposed the individually isolated object mask corrections on top, and then combined the three isolated object masks into a new single mask and used that to apply a high contrast curve (to everything outside the mask) before adding a glow to the whole. Its a bit extreme obviously, but hopefully it illustrates that, if you manage the tree carefully you shouldn't need to keep re-tracking the masks:

Go Nuts.png (863.12 KiB) Viewed 1472 times

That is it!! You're my absolute hero. Thank you so much for your time.

I may have spoken too soon. Everything was working great. I wanted to go back a few steps and hit command+z about 3 times WELL into the work flow and it cleared the tracking data on all 3 masks. Not sure why because I was well past 3 steps in the undo history (at least I thought). I wonder if there's a way to isolate a particular step in the undo history so that it will protect and lock in the tracking data. At least I know what the cause is. As long as I avoid "command+z" and rely more on the individual module undo features.

Yep, theres only so much you can do to protect yourself... at present, magic masks are inherently fragile.
If I understand it correctly, as currently implemented, 'magic masks' (AI masks derived from strokes) are stored in the cache folder - only the strokes themselves are stored as actual project data - so, by design, they are considered by Resolve to be temporary items. Anything that you do that might conceivably invalidate cache, intentional or otherwise, can affect them.

Bt they way, given you lost them this time with an 'undo', it's maybe worth noting that, unlike elsewhere in Resolve, the undo stack in the Color Page is not 'individual action' based, so it may be worth proceeding with a little caution when you start mashing 'Cmd Z'! ;)

Cheers
Andy