I've been working on some heat waves from a hand dryer, that distort a movie.
We have shot a normal hand dryer in foreground and a woman in the background. I now want to add heat waves and a distortion of the woman in the background.
But my problem is, that the displacement has to be set to the whole movie and if I distort it, also the hand dryer in the foreground will be distorted.
Are there any tipps of how I can prevent parts of the movie of not being distorted at all, but kept totally uneffected while the rest is being distorted?
Did you shoot the elements seperately? If not, naughty!
Dave's Stock Answer #2:
When you're out on a shoot, and you say, "we'll fix this in post" without knowing PRECISELY HOW you're going to fix it in post, don't shoot it! You'll only end up shooting it over again.
Since post typically costs three times the cost of production, fixing something in post is not a way to save money, but rather a way to spend more of it.
And, before you say "we'll fix it in post," always consider who's doing the work, especially if you're the one doing the editing.
- Dave LaRonde
Now, that being said, you will have to rotoscope the hair dryer on its own layer and put it above the background layer and heat waves.
Here is a useful page on rotoscoping: [link]
The problem is, if you don't have the hair dryer and woman on seperate shots, you may have bits of the hair dryer showing up distorted around the edges. You may need to try to clone it out. Pray to your deity of choice that you have a clean plate shot without the dryer in it that you could use instead.
- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')
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