How to do a stop motion effect with the lead actor moving ?

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plainman007

Well-known member
Hi,

Any ideas how we can achieve the same effect that was done in the matrix where they freeze an entire street except for neo and morpheus walking around those frozen people etc while hes talking about the design of the matrix. Ive also seen a movie where they froze an entire street and the actor crosses the road walking around all the frozen objects and after he reached the curb, The traffic continued from its frozen position. Any ideas how we can do this within Vegas ? Is it possible ?
 
On shots like those, they might be using a motion control rig (about $15k/day)... which can repeat camera moves precisely.

2- One potential method of doing this:

Shoot three things (with a locked-off camera, unless you have a motion control rig):
A- The background with people and traffic
B- The background without people, traffic, or the talent
C- The background + talent moving through it

B: If you can't shoot this, then just shoot A and average all the frames together. This should give you a clean background shot; the averaging will get rid of noise.

From there, pull a difference key between B and C. You want to just isolate the talent. Use rotoscoping to clean up the difference key.

Superimpose that onto A. If people or vehicles cross above the talent, you will need to rotoscope.

Shooting with an extremely high shutter speed will get rid of motion blur, which may be desireable. It's hard to rotoscope stuff cleanly when there's motion blur involved. Shooting outside during daytime will allow you to shoot with a very high shutter speed.


I think that would work... but you should test this out beforehand. To rotoscope, Vegas is not the greatest although it can be done via bezier masking. It'll just take you longer in Vegas as compared to programs like Silhouette Roto, Commotion, etc.

Vegas can do difference keying.
http://www.sonymediasoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=447861

3- Another potential approach would be to shoot this greenscreen. I think this would be more complicated.
 
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I'm sure it's possible, but keep in mind you're talking about replication huge effects shots with $400 software. If you approach the problem like that, you're more than likely going to be disappointed with the results.

On to the problem: I don't specifically KNOW how they achieved those shots, but if I had to guess I would decidedly say it's a mixture of techniques. Probably a fair amount of rotoscoping combined with mannequins and CG people/objects inserted afterwards. Some of this stuff is easy to do. Some of it is not. The important thing is to think about the amount of PLANNING that went into these shots before the first foot of film was rolled. Unless you have a comprehensive plan, your shot is probably going to fail.
 
Hi, Thanks Glen and Doug.

Ive seen this done on a really low budget native language film here in my country where these guys dont even know what a motion control rig is. LOL. So i figured there should be a simplified way to go about it. But ofcourse youll are right that Vegas isnt going to recreate the perfect effect that we saw in the MATRIX. That would be madness. But at least a sorta surreal replication of that effect is what i was looking at. When i say surreal i mean like the movie ULTRAVIOLET. If you noticed that movie's graphics was not striving for realism. Quite the contrary they aimed for a sketchy comic book look. The graphics thruout that movie looked obviously "drawn on". Regarding the planning. In the film made in my country the film seemed to pause and suddenly take on a 2d look. As if it was a still shot. Then the actor walked thru between vehicles etc and hoped onto the paving then the motion started continuing. I guess this can be done thru freezing the velocity envelope. Then adding one more layer of a still grab to the composition in vegas. Then adding some bezier masks around vehicles etc which need to be in the front of the actor and the rest transparent. But my only question is how do i show the feet. If i do this method then its more like green screening. Freeze frame and mask objects to be on the front. But my understanding of this concept covers upto torso shots and where the camera isnt moving. I cant understand how to show him running across the road (which means the camera is shooting him from the roof of a building or somthing). In this case id have to do something like what Glen was explaining. A combination shot. But i dont get how to combine them. He was saying something about shooting with traffic. Then without traffic. Now how do i combine the two ?
 
If you have your talent standing still (or moving very slowly), you can use motion blur or velocity envelope effects so that stuff moves around the talent.
 
This would be so much easier to explain visually, but here's a try:

Assuming you're talking about a single locked-off shot where the talent doesn't actually interact with any of the frozen objects, not hard. You would shoot one shot of your talent's movements (with nothing else in the scene moving anywhere near him), then another shot of the background/motion/traffic. You would make deadly sure not to move the camera even a hair in this process.

Then, in post, you would play your traffic footage until a point where your character's path through the scene would be clear, or close to it. This may be difficult to achieve without having planning/control over the extras/traffic. Then, lay in your talent on a layer above that and mask it down as close as possible. Voila.
 
Hmm just thought of something:

If you shoot outside, cloud cover can really screw you up since this changes the lighting. So you'd have to shoot when clouds don't factor in.

Also shoot very quickly all the shots, since the sun will move and slightly change color temperature. Avoid the hour close to sunrise and sunset.
 
I've seen this done with a combination of Photoshop and After Effects. Making 3D layers and moving cameras in 3D space. If I remember right they blue screened the talent walking because they wanted the shadows too.
 
Yeah i also thought blue screen might be the right answer.

Glen i understand your idea last mentioned. But there is a small problem. If i cut out the talent. Then there wont be anything in front of him to show that he is going between. This will look like a lay-on. A superimpose. But im looking at a scene where lets say 5 people (instead of vehicles so you can understand my concept better) are frozen. The idea you've suggested will only allow the actor to be on the foreground. I wanted him to look at a few of the frozen people then walk around one of them. Which means he comes over and is now between the camera and one of the people. Then moves around that person circling them. Which makes him go behind them also. I thought for this id have to duplicate the frozen frame onto another track and then draw a bezier mask around the frozen person and have that mask out the actor to show hes going behind that frozen person. What do you think ?
 
Glen i understand your idea last mentioned. But there is a small problem. If i cut out the talent. Then there wont be anything in front of him to show that he is going between. This will look like a lay-on. A superimpose. But im looking at a scene where lets say 5 people (instead of vehicles so you can understand my concept better) are frozen. The idea you've suggested will only allow the actor to be on the foreground. I wanted him to look at a few of the frozen people then walk around one of them. Which means he comes over and is now between the camera and one of the people. Then moves around that person circling them. Which makes him go behind them also. I thought for this id have to duplicate the frozen frame onto another track and then draw a bezier mask around the frozen person and have that mask out the actor to show hes going behind that frozen person. What do you think ?

Yes, as mentioned in my earlier post you'd have to rotoscope the cars/whatever in that situation.

With a blue screen I think you would have the same problem.

Depending on what you do, you might be able to cheat by having people stand still??? Although you gotta make sure they really don't move.
 
Now thats a tall order. LOL. Thats a very difficult thing to do unless you have trained actors who can absolutely look dead on with not even a flinch of the eye. But like you said depending on the shot we can actually cheat a lil.
 
You need a green screen and an object also painted green ( or you can use a mask like you said but it will be tedious and time consuming though wort it). You film the actors doing their part then you film the other scene with the general crowd moving around, or still shot.

Then you'd need something more powerful than Vegas, most likely After Effects since you're on a pc. You'll chroma key out the green thereby superimposing the other image onto the green areas. In AE you'll want the green screen layer on top of the crowd layer.

Their might be more to this as well. As far as cleaning up edges and what not.
 
what if you just have all your background actors stand still at a given Q? It worked for City of God.
 
Just like zoostory said, just have everyone stand perfectly still. I'm not certain about THE MATRIX, but I know for X-MEN 2, if you look closely enough when Pyro messes with some kids near the beginning in the library, and catches one of their sleeves on fire, when they're all frozen still ... the actors are just standing still ... watch REAL close, and you can see SLIGHT movement in some of them.

Then, just add the CG FX onto the footage to further the illusion that things are frozen still ... i.e. car was starting to peel out, so the car now sits still with the actor moving around it, while you motion tracked some 3D smoke around the tires, etc. While Vegas can't do the motion tracking of 3D smoke, you don't have to have a $15k/day rig to pull of a high production value shot.
 
Finn said:
Then you'd need something more powerful than Vegas, most likely After Effects since you're on a pc. You'll chroma key out the green thereby superimposing the other image onto the green areas. In AE you'll want the green screen layer on top of the crowd layer.
Click to expand...

Indeed AE has more powerful keying tools, but Vegas of course can handle quite a bit of green screening as well. Just making a point that spending another $900 or so on AE may not be necessary.
 
But how do they do that scene in XMEN where they are in a training room. Then all the objects CAR etc turn into wire frame objects ? They used real 3d applications or just 2d compositing ?
 
HI Envision. I work in 3ds max so if my opinion would be they created 2 renders of the same 3d scene. one with the materials etc on the 3d geometry. The second render in wire frame. Then they just have both overlapping and mask out the materialed render plate in a smoked fashion thereby causing the objects to appear to turn into wire frames while the cam is moving. Meanwhile do you work with the dvx 100 id like to ask you some specific questions if i may pm you ?
 
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