Hi, I'm new to after effects and I was trying to follow this tutorial on youtube,
Before I got stuck at 2:42.
In the video, the guy's mask path keyframed when he moved the rectangle downward.
For me, when I moved clicked on the mask path stopwatch at the beginning, and moved the time slider 20frames later and moved the rectangle downward, the keyframe didn't register.
So, I manually added a keyframe and when i replayed, there was no movement. And the mask path didn't reveal the other different smoke patterns like the video. Instead, when i manually moved the rectangle down, it was a still image of the same pattern.
It sounds like you didn't have the Free Transform feature enabled. Double-click on the mask itself and the Free Transform box will appear. Then click-drag the mask and the whole box moves, which moves the mask. When you do it on a frame after the initial mask path keyframe, you make a new keyframe.
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA