Help on straightening a bent straw!

[Joseph W. bourke]

Steve –

There are a couple of ways to do this, both requiring lots of time and money (just remember “Good, fast, or cheap…pick any two”).

The first one, and the one I would suggest, is to shoot the shot without a straw, using a motion control rig, then import the tracking information to use to place a 3D straw in the scene (created in Max, Maya, etc.), and animate the “erection” of the straw using some refraction effects to realistically bend the straw in the liquid (you didn’t say what type of liquid this is) and some colorization to make the straw look as if it’s really in the liquid. This method would give you complete control over the move, with perfect repeatability, and the tracking points you need to make the straw match without doing it frame by frame. You probably want to end up with at least two passes, one in which focus is pulled, so that the glass stays in focus throughout, and one in which the final lighting and depth of field is in place, which you’ll want to match in your compositing software (AE I assume).

The second one, and the cheaper one, would be, as you suggest, to use a practical straw with fishing line, or maybe some sort of mandrel inside the straw which would straighten it out? This one could take seventy five takes to get it right, with no guarantee that it would work.

I can’t imagine that there’s any effect within AE that could warp just the straw within a scene without having it look fake. I suppose you could shoot the shot with the straw against a green screen table cloth and try to pull a key. That might give you the straw clean, and you’d have a better chance of doing the warp believably. Good luck! It’s a challenge.

Joe Bourke
Art Director / WMUR-TV

[Steve Drew]

Thanks heaps Joseph. Unfortunately, this is definitely one of the Cheap and Quick selctions… and no MoCo rig is available.

I’m thinking of getting the director to shoot this in a series of plate shots – background only, then glass only, then glass with hand placing the straw etc… just so I’m somewhat covered. Once I separate the straw from the background I’m probably going to animate a ‘reshape’ effect to get the move right… then it’s probably half a day of jiggling so it doesn’t look too crap.

I’ve also just been told final resolution will be MPEG1, so I might be able to get away with a bit more than I had thought! 😉

Cheers,
Steve.

[Ryan Hill]

Have you considered stop motion?