Combine selective mattes in Image

How can one combine mattes generated with the selective in an Image node? I’m used to doing this with Lustre (add, subtract, etc.) but can’t figure it out in Flame.


Hi Matt!

It depends on which generated selections you’re referring to but the basic Gmask Tracer mattes can be combined over here:

The default is add but if you set it to subtract it does what you would expect:

There are a handful of variables relating to how you’ve added the masks, what they’re hooked up to, etc. And then it does admittedly get more complicated when you involve things like Machine Learning based keyers, but that’s the jist of it.

Hope that points you in the right direction but let me know if it doesn’t.

Thanks for the reply. I should have been more specific. I want to take the matte of, say, selective 1 and subtract it from the matte of selective 2. I’d be using keyers and masks in both selectives. Lustre does this easily with the little eyeball icon so I figured there is probably something similar in the Image node but I haven’t found it yet.

Gotcha. To my knowledge I don’t think the Image node can do that yet. You can do things like use the same Gmask on two selectives and have one selective set normally and one selective set to outside but that inverts everything. You can create some complex shapes within one selective using multiple gmasks, but I don’t think you can have one gmask that is set to Add on one selective and have that same mask set to Subtract on a different selective without duplicating the mask.

But it could be me! Maybe someone else knows. But in my adventures with the Image node I don’t know how to do that either.

Hi Jeff,

This is a tricky one because each selective is a separate process coming off the image. Interestingly enough, there are pipeline adjustments in the Selectives which can indeed affect the result of each selective on each other but this does not include the matte. So the short answer is no.

However since we don’t like saying never with Flame :relaxed: It is possible to use the Selective Matte Extraction SelectiveFX shader to get each matte out and then combine them in a separate Comp node. I was able to do this with one action node and multiple outputs. For each selective, apply a selective matte extraction SelectiveFX. At this point they will not combine, just overwrite each other. So using the Action output, make two outputs and assign/disable one selective per output. With the two outputs from action, combine them in a comp node and job done!

Please log this as a feature request in Flame feedback.