Keying a green person and replacing him?

[Hugh]

I'd imagine they'd shoot motion controlled, and have a clean plate pass - this would provide what would be put in behind where the green suit was originally.....

[Mananetwork]

now thats what I figured first.. I've never worked at a film company and don't know much about their budget and time. That would be one option.

[Hugh]

If it's a locked off shot, they could easily get a clean still from it....

For a moving camera shot, I can't think of any other way...

Anyone else got any thoughts?

[Mananetwork]

If it's a locked off shot, they could easily get a clean still from it....

For a moving camera shot, I can't think of any other way...

Anyone else got any thoughts?

Well most of those shots you saw they panned and some even changed perspective

[Oxide]

I think I read somewhere that they shot motion control, unlike most of the Gollum shots in the LOTR trilogy.

[arvid]

It's probably similar to what they did on Hollow Man with motion control

[JohnnyRandom]

I have to do some bluekey for a short film but my question is what is the best format to export my DV-footage
Just an FYI, You should use a green instead of blue. In DV format the green spectrum has the most information in it. Blue is not the ideal color to key DV footage.

If that is what you meant, then please disregard my post :)

[beaker]

There are a few ways to do this. If they didn't shoot a clean plate there are still options.

If there is enough data from the shot you can use something like Mokey to create your own clean plate which uses information from frames before and after a frame to cut out an object (Pixel Farm has a product that also does this, I believe PFTrack can and they have other products).

Another way the more manual approach of what Mokey does automatically. You can track a shot and then use frames from before and after with painting and some roto to reveal the missing information. This is a lot of work but can happen.

The other option is to recreate the background in 3d with simple camera projections and basic shaped models. First 3d track the shot, then use that as a reference for modeling the scene. If there is enough data I will use an image modeler like Imagemodeler or PFbarn. Project textures from the shot directly onto geometry. Anything that you don't have enough data you just have to recreate by painting the textures.

[Aneks]

Don't know for sure how this was done for this film probably have to have a read of cinefex to be sure.

BUT

Generally motion control is too slow and cumbersome to work on dynamic shots with live action elements. Now days it is generally used to do low - speed photograhy, minature work and shots where the mainfocus of the shot is easy to work at different speeds ie a car commercial. Shots where sonny is interacting with the environment or mechanical objects or 'gags' could certainly be done with MoCon rigs.

Most of the time a 'clean plate' will be used in a lock-off or simple camera move where the camera action can be replicated almost exactly or re-timed if it does not match the live action take precisely. Otherwise you are gonna have to 'brute force' it, and use similar techniques to a rig removal and do patch replacements and complex paint/roto's to repair the background which was occluded by your actor in the suit.

Alot of work I have done recently on this sort of fotage relies on camera matchmoving using standard tools and digital extensions either in 2d, 3d or both to patch up holes in footage. Sometimes with projection mapping sometimes just fudging it with painted textures.

The 'Hollow man' technique referred to in this thread , that is using a variety of motion control camera which records the movement of the camera dolly, crane or mount and then recreating this action in subsequent takes may have been applied to this film. This technique is cool but has severe limitations as, like all motion control it cannot perform fast truns and dramatic speed changes with the same pace and fluidity which is now possible with some of the more complex camera riggs currently employed in filmmaking. This is why, if you look closely on the hollow man behind the scenes' stuff the set was cleared and then the rig with camera attached repeats the motion at a slower pace shooting at a different speed.

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