Reverse Scale

Moderators: Disciple, zlovatt

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Posts: 1
Joined: December 5th, 2008, 3:56 am

December 5th, 2008, 4:32 am

Hi Guys,
I'm kinda new to the world of expressions but I really want to start using them more often (would save me a LOAD of time at work. Anywho, at the moment I am working on some green screen work (Kinda like a Sin City recreation for an advert we are working on) I have had to track some actors in a car (using Mocha AE (for CS4)) and it has done an amazing job at tracking so i can stabilize this crazy Jib/dolly shot. At them moment, the scale keyframes shrink down the footage (mirroring the scale of the car as it moves back into the distance) but what I want to do is reverse the keyframes (with an expression) so the portions of the car stay the same (scale wise) as the camera moves back (so it should result in an effect similar to a dolly-zoom).

so in short, I want to reverse the scale keyframes so that instead of the footage getting smaller, its gets larger.

Could anyone give me any help/pointers? :?

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Posts: 460
Joined: June 17th, 2004, 9:27 am
Location: New York City, NY

December 5th, 2008, 3:02 pm

try this:

Code: Select all

value *-1
Posts: 128
Joined: December 7th, 2007, 10:11 am

December 7th, 2008, 10:09 am

If I understood correctly, I think he needs something different.
Try using: 10000/scale
where the scale is taken from the tracker, and applied to the tracked layer.
This will make smaller scale to grow (for example half size scale of 50%, would become doubly big: 200%).

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