Hi there,

I am trying to build a showfile where you load a background image, and through the Key/Fill input setting under 'Color Key' Corresponding frame greyscale cutout images are used to punch holes in this background image. The plan was to create multiple multilayer inputs referencing the background input on layer 1 with the different greyscale images acting as the key/fill input for each of these multilayers (essentially meaning that you can swap the backdrop out, and instantly populate alpha overlays of a 1 box frame, 2 box frame etc.

The issue that im facing is that the Key/Fill input setting only seems to work on the input itself, and will not work at all on a multilayer. Any suggestions or is this just a limitation? (Running vMix 24)

This is by design. The devs have stated that they intend for mixes to be the way of flattening an input and applying an effect. I believe these were introduced in vMix 25.