Blackmagic Forum

Hi to all,

I' m not expert about Fusion (and compositing in general) so I'm sorry if my request / doubt is simple (as I imagine).

I have a problem about the combination between Primatte (or Ultrakeyer) tool and a Polygon mask.

In other words, I take a footage with a green screen, and I apply Primatte tool to remove green without problem.
Since I want to remove some objects from the footage, I use also a polygon Mask, but when I connect it to Primatte tool, the green screen reappears again outside the masked area (or inside the area if I flag 'Invert mask').

I attach two screenshots showing an example before and after connecting the mask.

So I wuold like to ask you where is my mistake...How can use a mask on a keyed footage mantaining the transparent background?

Thank you in advance.

Paolo

Hi Paolo - you should connect the mask to the garbage mask input instead of the effect mask input. Currently you have got it connected to the effect mask --> this limits the effect (i.e. the green screen) to this mask to this area (rather than acting like a garbage mask and taking it out altogether).

EDIT: and in your case you also inverted the mask, so it only then performs the green screen effect on the image outside of your mask.