Hi, newbee here. I'm doing my best. I'm following The After Effects Apprentice on LinkedIn Learning and am attempting my own super simple animation and I'm a bit stuck.
I want the red rectangle to reveal the text "and i" but the speed is out of sync and so the "a" come out at the same time but from "n" the matte goes faster than the red rectangle, and so the text is revealed before the rectangle covers it, if that makes sense.
How do you sync the speed? I was thinking it might be the Keyframe Velocity, but that made a different kind of mess.
As you've correctly guessed, it's the keyframe velocity. Looks like your "red thing" keyframes are easy eased (hence the hourglass shape) whereas the matte keyframes are standard linear keyframes.
There are two ways to fix this: You can right-click the red thing keyframes, select "keyframe velocity", take note of the influence in/out values then apply the same influences to the matte layer's keyframes by going to the same keyframe velocity menu. or
the most common tool people use all the time to copy keyframe easing from one set to another is a script called EaseCopy (https://aescripts.com/easecopy/). It's a name-your-own-price script that does the above but with only 2 clicks.
I actually had this problem on two part, what you instructed me to do worked on one but not the other. The only thing that is different is that before the "red thing" moves, I have a hold key frame for a few frames. So
1) the red thing reveals "made by you"
2) pauses for a beat (hold key frames)
3) starts up again in sync with the mask for "and i", but the mask moves faster.
I've spent almost an hour tweeking the times in the Keyframe Velocity and it never fixed the problem, just delayed it or switched when the separation happened.
Do you -- or does anyone -- have any other suggestions? So far, I've been animating the Anchor Point. Would animating the position make a different result?