[lucas pelus]"it's easy to disepear one word but two words one under another it's becoming tough."
Yeah, tough is a great description indeed! I'm guessing they used a Text Plugin to do this. Vegas has some, and yes they do come close to what you want, but each one, for this manipulation would be less than adaptable resulting in madness! Personally, I'd reach for my NewBlueTitler Pro5, it'll do this and much much more . . .
However, if you don't wish to spend the money then try EACH word on a separate Track and get the sync within Pan/Crop or Track Motion to make words slide-in, disappear etc etc. You'd get far more control and be able to get what you want. Now, if you want to adjust your results in and out of your MAIN video set up your Text VEG Event as a Nested Veg and you can have more control and NOT confuse your Main video - yes? Votre anglais est bien mieux que mon français!
Video Content Creator and Potter
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