Same actor twice (or more) in one shot

[cheeseandachallenge]

In a couple of scenes I need to have my actor twice (or, preferably more) in the shot. It's kind of hard to explain, but essentially a previous iteration of the character exists in the shot, and the current 'version' of the character can see but cannot interact with her. So when she tries to touch the other version of herself, she just passes through.

I am not at all talented in after effects or any sorts of special effects, so I am really unsure how to go about achieving this. If they two versions of the character didn't have to physically pass through one another I'd just do two tripod shot and crop them together, but, yeah... any ideas? I tried to do some tests with just playing with opacity, but then both characters both look cheap and half invisible.

Thanks in advance

 

[Will Vincent]

You're not going to achieve this without rotoscoping and compositing.. Wether the rotoscoping is done with a green/blue screen or by hand, that's the necessary piece to composite two copies of a person into a shot.

Unless you're shooting film, in which case you could black out have the gate, film the action on half the screen, then black out the other half the gate and run the film through again to capture action on the other half of the screen.. but there wouldn't be any interaction between left & right then.

The specific term that you're looking for, that you'll need to learn how to do, is "travelling matte"

But that's the the beginning. That'll allow you to get multiple instances of your actor on the screen, but you'll need to also figure out the interaction. Even just to have one pass through the other, that'll take some additional masks and compositing work to make it look like anything other than two pieces of video composited together.

Perhaps you need to hire a VFX person, or simplify your story.

 

[harmonica44]

I tried out doing the effect myself, but for some reason I get bigger, when I try to walk through myself. I marked my feet with tape so I knew where to walk through. I guess I was still off. And for some reason their is that white noise crap, that keeps flashing on and off!

http://youtu.be/seX9nVlYLGE

 

[Toxoiid]

I'm working on a project that calls for similar effects.

I did some tests and I found the best way to achieve this effect was through green screen. If you need some help, send me a PM.

 

[KnightsFan]

If you use a greenscreen, you could put up green only where character A is supposed to stand while filming character B. It would be less keying to do.

(Does this make sense? I'll draw some pictures if it doesn't.)

 

[Will Vincent]

@KnightsFan I don't think that will work very well given the requirement for the two (or more) instances of the actor to occupy the same screen space.

So when she tries to touch the other version of herself, she just passes through.

 

[KnightsFan]

So when she tries to touch the other version of herself, she just passes through.

Yes, exactly. So what you need are both characters in their entirety on every part of the screen, separable from their background over the part where they intersect. The parts of the screen where they don't intersect are irrelevant so there's no need for green screen there.

Actually, come to think of it, you don't need any green screen at all if you already know how everything will layer, and if both are fully opaque. It could be done with a simple motion tracked mask, if your actions aren't too complex. I was assuming the characters just touched, but if they're supposed to dance through each other or something it'll get more complicated.

 

[Caidh Mor]

I tried out doing the effect myself, but for some reason I get bigger, when I try to walk through myself. I marked my feet with tape so I knew where to walk through. I guess I was still off. And for some reason their is that white noise crap, that keeps flashing on and off!

http://youtu.be/seX9nVlYLGE

It looks like you're walking through at an angle while shooting wide. The foreshortening caused by approaching the camera will make you appear to grow in size. When shooting wide you'll increase in size much more quickly.

 

[Will Vincent]

It could be done with a mask even if the action is complex, but that's the whole point of greenscreen to begin with, simplifying creation of that mask.

 

[KnightsFan]

True, I was just pointing out that simple actions are simpler to manually mask.

But anyway, it will need a mask somewhere, because one character has to be clipped away based on the other character's position. Unless they just cross arms or something super simple like that.

 

[Caidh Mor]

Honestly, most shots like this can be dealt with best in the cut. Lock off a setup, film the actor playing both parts, but avoid crossing each other. When going OTS, use a double.

 

[harmonica44]

It looks like you're walking through at an angle while shooting wide. The foreshortening caused by approaching the camera will make you appear to grow in size. When shooting wide you'll increase in size much more quickly.

Okay thanks. That's interesting. Let's say you have a scene where one actor standing, and another actor has to walk towards him from a diagonal direction. How do you stop the actor from being twice the size when they are right next each other? Cause lots of movies have wide shots, where one actor will walk towards the camera, but not appear to be twice the size, once lined up with another actor.

 

[Caidh Mor]

Okay thanks. That's interesting. Let's say you have a scene where one actor standing, and another actor has to walk towards him from a diagonal direction. How do you stop the actor from being twice the size when they are right next each other? Cause lots of movies have wide shots, where one actor will walk towards the camera, but not appear to be twice the size, once lined up with another actor.

Math. Math is how.

Seriously, though, there's a lot of complicated math behind puling the effect off properly. Different lenses will likely require you to cheat differently. A wide lens exaggerates movement within the depth of the frame. A longer lens diminishes it. If you were to set up the scene with a similar framing, but by moving the camera back significantly and switching to a longer lens, the foreshortening won't be as pronounced.

Here's a quick read, just jump to the sections about Perspective and Perspective Effects.

To blow your mind further, here's a quick look at some use of Forced Perspective, a similar topic. This example comes from Peter Jackson when he did Lord of the Rings.

Alternately, the guess-and-check method can work too. Just alter your trajectory in some test shots, go with what looks right.

 

[harmonica44]

Okay thanks. It's just weird cause I have never had two actors stand next to each other and have one look closer than the other if they are the same distance away. I am reading the article now! I don't mean to steer this thread in another direction from the OP, but this could help achieve the effect as well... What's with the flashing white noise on the video, after attempting to composite the effect? I tried it again, but still got white noise.

 

[Caidh Mor]

The weird static is probably some error that recurs in the render. Try changing your render settings.

The problem is that you weren't the same distance away. The beginning of the shot's actually pretty decent, but when you're that close to the camera, a small shift in position fore-aft in the frame translates to a huge change in size. If you made a few takes, each moving more shallowly across the screen, I'm sure one of them would eventually line up.

 

[cheeseandachallenge]

Unfortunately don't have access to a green screen, and have to shoot tomorrow (using a flatmates currently unfurnished bedroom, but he arrives in a couple of days). The actors have to cross paths at least a few times. So I guess rotoscoping it is.. unsure if it's a bit beyond me (have never really done it before) - is anyone here willing to help?

 

[pictureplanet]

Yikes.

 

[cheeseandachallenge]

If that yikes is directed at the schedule/the lack or pre-pro; it was something a friend and I wrote a few days ago. I'll direct, she's acting. It's more of a whimsical fun thing. If we had the location available for longer, of course we would put a lot more work into it. But as it stands we're just kind of doing it and hoping for the best, and if it doesn't work out it doesn't matter too much