I saw a TV commercial that I can no longer find (or ID) in which an actor was walking in a park when, 3-4 seconds into the footage, he "split" into two instances of himself and each walked off in a different direction simultaneously. Can anyone help me figure out how such a VFX might have been done? I'm thinking some kind of split screen with roto work, but I can't quite figure it. Thanks.
One of the common techniques for this kind of effect, if no motion controlled rig is available, is to shoot a static shot at 4k with the actor walking twice in the shot- starting in the same point and then follow each direction one time. Camera travel/move and shake can be then added in post.
Another down and dirty trick I like for lining up 2 different takes (right at the split point in your scene) is to have a field monitor so you can play back your first take. Pause it right when you want the split to occur and use a dry erase marker to trace the actor's outline on the screen (you may want a clear plastic screen protector over your screen depending on the surface).
Line the actor up with the outline you traced and roll subsequent takes. This should give you a very close match for your split point. You can use warping tools to get the exact match.
Thanks. Your ideas have lead to a concept I will experiment with once the results of Hurricane Sandy are cleared out of here. The actor will walk along a path and at a specific spot, change to heading to a different destination. A second shot will be of the actor starting in his best estimate of his pose at that spot then walking off oppositely. The second shot will include a green screen behind the actor.
In post, the two plates will be set up with the second shot on top. With its opacity reduced, the two layers will be synchronized in time as closely as possible in terms of position.
Then, the green screen layer will be keyed to yield a decent alpha channel. Layer one will also get the puppet tool applied and animated to distort the second shot to a very close fit to the first shot. The distortion should not be so bad as for the actor to appear distorted and the animation need only be a handful of frames to smoothly remove the distortion. The bottom layer will fill in where the green screen was. Several shots may be needed to get one good one and a field monitor would be very useful.
This would work in reverse as well to bring them back together into one later.
If need be, maybe a dog running past at the critical moment barking as it went would be just enough to draw attention and allow the illusion to unfold unnoticed.