Using a mask to apply an FX to only part of a layer

In this guest tutorial we're joined by the Rockwell Group's LAB division who work as an interactive design team within the larger architecture firm where they focus on projects that blend physical and virtual spaces.

For a recent projection mapping installation in NYC, one of the techniques used by the LAB was to apply a real-time video effect on to a specific portion of one of the pre-rendered movies such that part of the image was left unprocessed in the main output while another section was color shifted to match the lighting effects in the room.

To begin, two movies are loaded into VDMX – the first is the original media of the complete statue and the second is a black and white movie containing just the robes. Next, the Layer Mask FX is used with the black and white stream as its source to describe where the hue shift should be applied.

Another handy trick in this setup is that the original content is sideways – this is because the actual projector has been rotated, set on its side to get additional vertical resolution and uses perspective correction to compensate for the projection angle

Tips and Notes:

Preview windows showing each layer and how they are combined for the final output.

Sync the playhead of the masking layer source to the movie layer time.

Set the background to receive the movie layer output before any FX are applied.