Reverse Scale Expression

In the Demon Face Warp Tutorial we learned to reverse track by adding expressions. One expression reversed the rotation by multiplying it by -1.

Now I had a question about reverse scaling… I didn’t know, until now:

Basically you create a variable inside the final comp where you apply the reverse rotation expression but instead we alt click on the scale and write
m=100/comp(“yourPreComp”).layer(“originalLayer”.transform.scale[0];
value*m

So if m=400%, then 100/400=.25, and .25*100% is 25%. And 25% of the now 400 percent image is now back to the original size.
To create the layer variable, you can pickwhip the scale of the precomposed layer as shown in the tutorial. Then add [0] so that you only use one of the scale values for the width.

Try it out and hopefully you can use it in the future.

EDIT for Clarification: When you motion stabilizing something with 2 points you can calculate the rotation and scale from the Motion Tracking Menu, this scales up or down as needed to keep the 2 points the exact distance appart. Thanks for bringing this up Kyle, I’m tired too.

POSTED:
10 years ago
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