There is a name for this but my failing memory....

Alpha channel wipe/transition?

Mike

Yeah, that's the way you do it. Make a .png following the below idea, and put it on the timeline above the track(s) you want to mask, then use track motion to move it.

All transitions are "motion masks".

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Imagine taking a sheet of paper and using various sized hole punches
make a multitude of aligned holes. The paper sheet becomes a mask
for a transition as you move it in front of the lens

Its called halftone dots

example on left


now to find slightly higher resolution examples.

(I want to see the dots!)

Illustrator or CorelDraw can do that. It's done with the "blend" tool. Make a big circle and a little one, select both objects, then use the "blend" tool and tell it how many steps.

Want me to make one for you?

Try the Sony Vegas Newsprint FX. Lots of variables there.

Grazie

I think the OP is trying to make a motion mask, am I right? In that case there is no halftone pattern, only smudge patterns.

Thanks folks,

Newsprint is what I am going with.

This is for a customer that is going from a printed format to internet
subscription only. So a video transition from the halftone image to
full clarity fits perfectly.

Thanks for your help.

I've used NewsPrint often in many different ways. If you blow it up real BIG you get a handful or just single DOTS!!! - I've then used this as part of an exploding LOGO. I had each DOT fly off the screen. - Client loved it.

Grazie