A moving green screen shot

TheMonkeyMan · Post by **TheMonkeyMan** » Tue Oct 19, 2004 3:41 am

Hello, Im new to this forum. Although I have been looking around this site and other video sites for a while. What a great forum!

Anyways.... I was watching a skateboard video not to long ago called "Yeah Right!". In that film there is a scene where they green screen the boards out of the picture, so it looks as if they are riding invisble boards. Now some of the shots the camera was steady and just pointing in one direction, which is easy to figure out how they did those, but they also had shots where the camera is moving and filming the skater while the boards were invisible. I was wondering how they green screened the boards out of those moving camera shots since it would be very difficult to do the EXACT same camera movements for the empty picture then move the camera the exact same way for the part with the skater. Or is that how they did it? Any help would be great! Thanks

Carnage7p · Post by **Carnage7p** » Tue Oct 19, 2004 6:04 am

they probably just masked them out in post. something like after effects could do this. it might take a while but it is likely they did something similar to this. it doesn't matter if the camera is moving becuse they can just create an animated mask using key frames.

Syras · Post by **Syras** » Tue Oct 19, 2004 8:07 am

actually it would be very difficult to mask out a moving shot because it would be almost impossible to get a clean background plate that exactly matches the moving footage. more likely (depending on the budget of the film) is that they used a computer controlled camera (often they look like a dolly on a track housed in a big box). it can record its movements and repeat them an infinite number of times.

NaziSentry · Post by **NaziSentry** » Tue Oct 19, 2004 9:24 am

Or they had a shot that was bigger than the editing resolution and just moved the shot around in post?

I3lade203 · Post by **I3lade203** » Tue Oct 19, 2004 11:55 am

Syras wrote:actually it would be very difficult to mask out a moving shot because it would be almost impossible to get a clean background plate that exactly matches the moving footage. more likely (depending on the budget of the film) is that they used a computer controlled camera (often they look like a dolly on a track housed in a big box). it can record its movements and repeat them an infinite number of times.

If you have the track, then you line the track across the street, and then film the background shot. Then you film the person in the exact speed motion and angel of the other one. And most people can't afford a track like that, althougth Ryan W. was creative, he used his lego train track ( Thats still like what, 150$? ) which controls speed, and found a way to attach his camera.

V|Esquilaxer · Post by **V|Esquilaxer** » Tue Oct 19, 2004 9:50 pm

I saw that skateboard video and I was amazed at how well they did the job. It looked great, especially when it mind-boggles me how they could do such a thing with such accuracy

I3lade203 · Post by **I3lade203** » Tue Oct 19, 2004 10:44 pm

Mind posting a link?

TheMonkeyMan · Post by **TheMonkeyMan** » Tue Oct 19, 2004 11:10 pm

Yeah they did a VERY good job at editing that film, with the invisble board and the beginning of the film with the extrememly slowed down skatetricks was awesome. Here is the link to the trailer: http://www.rhinotransport.com/970247.lasso# It shows a scene of the invisible board on it.

I3lade203 · Post by **I3lade203** » Tue Oct 19, 2004 11:58 pm

Oh , it's a person without a skateboard. Yeah, a track would be preferable. I would not use a green screen for that though, masking is the way to go.

bangoker · Post by **bangoker** » Wed Oct 20, 2004 4:58 am

EDIT:

i erased my post, but for one strange reason i can click on the "delete this post " check, so....well you have this

TheMonkeyMan · Post by **TheMonkeyMan** » Wed Oct 20, 2004 5:32 am

Well I know they used green screening for sure, because they have a few scenes in the video of them riding completely bright green skateboards. So what exactly is masking? How is it different than green screening?

Syras · Post by **Syras** » Wed Oct 20, 2004 7:16 am

green screening requires a specific colour that can be "keyed" out. this is basically the process of telling the effects program that anything that is bright green is now invisible. masking however requires drawing a shape (the mask) on a layer and making that part invisible. you can use keyframes to make the mask move and thus cover specific areas (eg you could draw a skateboard shape and animate it frame by frame to make sure the skateboard is invisible for the entire shot). in both cases you require a background layer to replace the footage (in the skateboard case footage of the street behind). however to make this look perfect the front layer and the background layer must match up exactly

I3lade203 · Post by **I3lade203** » Wed Oct 20, 2004 12:00 pm

Masking is another form of keying. In theory, it's EXACTLY the same thing. One of them your telling the program , get everything of this specific color outta here, and in another the backgrounds whatever the hell you want, and you control what stays and what goes. Since you need no balance of color, you can light the actor however you choose when masking. With masking, it's a lot easier to background footage and mask the person in , BECUASE you just film the scene twice, one with the actor(s), one without. Mask the actors, which removes EVERYTHING but them, and place them onto the footage without the actors. There you go , you got the actor keyed now, and you can do whatever you want to each one(mask) without effecting anything else. Thats the whole idea with invisble skateboard, is the masked the skateboard and just well, got rid of it!

pan-modo_pictures · Post by **pan-modo_pictures** » Wed Oct 20, 2004 5:53 pm

The entire skateboard was just spray painted green. There was no masking involved. This was no ordinary skate video though, as it was directed by Spike Jonze.

I3lade203 · Post by **I3lade203** » Wed Oct 20, 2004 10:44 pm

That can work to. althougth if the greens lighting is inconsistent it can be a pain in the a** to key. Masking is more convienet for amatuers.

TheMonkeyMan · Post by **TheMonkeyMan** » Sat Oct 23, 2004 8:19 pm

I was just thinking, if you were doing an outdoor shot like that and there was other green in the background, like grass. Could you make a little selection around the riders feet and the skateboard, then key ONLY what is in that area? Then animate the selection, so it follows the skate board?

I3lade203 · Post by **I3lade203** » Sat Oct 23, 2004 9:20 pm

That's called creating a mask. No need to even paint the board green if your going to do that. You should read our posts becuase we described what masking was above.

TheMonkeyMan · Post by **TheMonkeyMan** » Sat Oct 23, 2004 10:08 pm

I understand what a mask is. I have worked with photoshop and flash animation for a while, so I know all about that stuff. But it seems to me that making a perfect mask around the board and not accidently getting his feet cut out would be very hard. Especially when hes moving.

BrownCowStudios · Post by **BrownCowStudios** » Sat Oct 23, 2004 10:14 pm

That shouldn't be a problem. Moving frame by frame, you can control the shape of the mask for each individual frame. Rotoscoping is generally not very difficult, it is just ridiculously and painfully time consuming.

I3lade203 · Post by **I3lade203** » Sat Oct 23, 2004 10:20 pm

TheMonkeyMan wrote:I understand what a mask is. I have worked with photoshop and flash animation for a while, so I know all about that stuff. But it seems to me that making a perfect mask around the board and not accidently getting his feet cut out would be very hard. Especially when hes moving.

Um, i'm not talking photoshop or flash. I'm talking affter effects.

TheMonkeyMan · Post by **TheMonkeyMan** » Sat Oct 23, 2004 11:32 pm

Yeah no kidding blade.

You're a quick one

. All I was stating was that I know what MASKS are, because I have worked with a lot of photo editing programs... Anyways, Thats why I suggested making just a small general masked area around the board, then keying the board out, so I wouldn't have to go frame by frame making sure the mask was perfect.

I3lade203 · Post by **I3lade203** » Sat Oct 23, 2004 11:35 pm

You have a lot to learn monkeyman, a lot to learn indeed.

TheMonkeyMan · Post by **TheMonkeyMan** » Sun Oct 24, 2004 12:00 am

Oh man, its Blade! The almighty video master! Bow down to him! I am by no means a good video editor I admit that, and im not saying im better than you or anyone else here blade, but when you act like you are the almighty wise one, when practically half of your posts are spamming garbage then that makes me quite angry. I wasn't trying to act like I knew everything about editing at all when I said I knew about masks.

Epsilon · Post by **Epsilon** » Sun Oct 24, 2004 1:32 am

lol This is a funny thread.

You can set masks to follow differences in footage, like a moving line, in After Effects. Though sometimes you just have to resort to frame by frame tracking. The dirty work of filmmaking!

I3lade203 · Post by **I3lade203** » Sun Oct 24, 2004 2:04 am

TheMonkeyMan wrote:Oh man, its Blade! The almighty video master! Bow down to him! I am by no means a good video editor I admit that, and im not saying im better than you or anyone else here blade, but when you act like you are the almighty wise one, when practically half of your posts are spamming garbage then that makes me quite angry. I wasn't trying to act like I knew everything about editing at all when I said I knew about masks.

umm... all I said was you have a lot to learn where do you get me saying im better then everyone? Oh and thanks for bowing down, you should do that more often. :Roll: Some people..