About this video
A Mask draws nothing and cuts other layers to its shape. The setting that catches everyone is Reads: Alpha or Luminance, because black and transparent are the same thing to the alpha shader.
Playable Ads Maker - playable ads and end cards, no code.
Transcript
On Luminance, a BLACK cut-out reveals nothing. Black means hide.
This card's glint is an ordinary shape. What keeps it inside the card is a mask.
Turn the mask off and the glint runs straight over the edge, across the background, past the chip. That is the difference a mask makes, and it is the only honest way to see one: not by reading the panel, but by watching what the viewer sees change.
Move a rectangle: a wipe. Grow a circle: an iris.
That is Mask, end to end. See you in the next video!