A truly "simple" invisibilty effect?
by Tom Westgate
on
Apr 29, 2008 at 3:26:04 pm
I watched Eran Stern's Invisible Cape tutorial which states it's a "simple method." However, to me, greenscreening your actor ahead of time isn't simple. It takes planning and preparation and equipment you may not have.
What do you do if someone gives you preshot footage of an actor in an environment and needs you to make the infamous Predator look?
Well, I'm no AE expert, but I'm trying! I had an idea based on Maltaannon's Particle Playground on Fire tutorial. If you take a locked down shot of a real life background (30 seconds or so), then have your talent act out their scene, can't you use the Difference mode to somehow cheat this effect?
I shot a short segment and am trying it out, but coming up a bit short.
So far, I used Tint to greyscale all the footage, and used Difference on myself when I "go invisible." I then precomped that and in a new comp, used the B/W version as a luma matte. I then used Colorama (grey ramp) and Posterized the original footage.
It is getting close to the look. But I'm sure our experts here could really make this shine.
Re: A truly "simple" invisibilty effect? by Dave LaRonde on Apr 29, 2008 at 3:32:37 pm
[Tom Westgate]"What do you do if someone gives you preshot footage of an actor in an environment and needs you to make the infamous Predator look?"
You give the footage back and tell that person to do some stinkin' PLANNING!!!
"If you take a locked down shot of a real life background (30 seconds or so), then have your talent act out their scene, can't you use the Difference mode to somehow cheat this effect?"
The results of a Difference Key are spotty at best, because the key is generated on matching pixels in the clean plate EXACTLY with pixels in the video... and if they don't, the transparency disappears.
When you're out on a shoot, and you say, "we'll fix this in post" without knowing PRECISELY HOW you're going to fix it in post, don't shoot it! You'll only end up shooting it over again.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: A truly "simple" invisibilty effect? by Roland R. Kahlenberg on Apr 29, 2008 at 4:09:42 pm
But the "Insible Man/Predator" effect doesn't require precise edges. The Difference Matte plus possible garbage matting, cuves and levels and matte chokes on the resultant matte should do the trick.
Cheers
RoRK
broadcastGEMs.com - the leader in customizable royalty-free animated backdrops
Re: A truly "simple" invisibilty effect? by Dave LaRonde on Apr 29, 2008 at 4:20:57 pm
[Roland R. Kahlenberg]"But the "Insible Man/Predator" effect doesn't require precise edges."
True enough. But it DOES require a clean plate. And by the tone of the original post, I doubt that one exists, or that the person doing the shooting even knew what clean plate is, or what the implications would be if the camera is in motion.
Our original poster had mentioned being handed already-shot footage. Is it hand-held? Does it arc around the subject? Can you salvage enough of the background to actually build a clean plate that would work? What about any motion blur in the background? What if it was windy? What if the sun ducked in and out of clouds? What if it's DV, with its notoriously poor color resolution?
I don't know about you, but I wouldn't want to reconstruct a clean plate given those circumstances. Too many ifs in my book.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: A truly "simple" invisibilty effect? by Roland R. Kahlenberg on Apr 29, 2008 at 4:34:30 pm
[Dave LaRonde]"Our original poster had mentioned being handed already-shot footage. Does it have camera motion in it? Is it hand-held? Does it arc around the subject? Can you salvage enough of the background to actually build a clean plate that would work? What about any motion blur in the background? What if it was windy? What if it's DV, with its notoriously poor color resolution?"
I thought he said that he had a locked down shot. No?
Otherwise, you're right for the most part. But then again because the effect doesn't require much perspective, it may still work. It all depnds on the actual plate and the desired effect.
Cheers
RoRK
broadcastGEMs.com - the leader in customizable royalty-free animated backdrops
Re: A truly "simple" invisibilty effect? by Dave LaRonde on Apr 29, 2008 at 4:49:47 pm
As I re-read the original post, his query about using a difference key did indeed involve a locked-down shot, and he was also talking about creating invisibility from already-shot footage.
Apparently, we're addressing two different questions from the same post.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: A truly "simple" invisibilty effect? by Mark Suszko on May 2, 2008 at 6:27:43 pm
I don't know beans about Aftereffects. But if your shots are locked down when shot or first motion-tracked to generate a locked down plate, you could then perhaps use difference key and then apply an image warp or displacement map to the key signal in a composite. This effect really counts on having a clean master plate, and if you don't have one you'll have to roto yourself as well as paint yourself out of the shot, just so you can paint yourself back into it as a displacement. On the bright side, the displacement is supposed to be a visible distortion (that we're pretending only we the audience can see, so it *should* cover a lot of imperfections in the painted-out layer. But I don't know anything about AE, I'm just dreaming out loud, based on what I'd try in Combustion.
I wonder if there is a way you could do this using particles.
Re: A truly "simple" invisibilty effect? by Roland R. Kahlenberg on Apr 29, 2008 at 3:58:22 pm
When using the Difference Matte, you don't need to create a B/W image. The Difference Matte will create a matte, which is inherently a grayscale image.
What you may want to do is to cleanup and perhaps tighten up the matte. AE's builtin Matte chokers should do the trick as well as Curves and Levels.
HTH
RoRK
broadcastGEMs.com - the leader in customizable royalty-free animated backdrops
Re: A truly "simple" invisibilty effect? by Dave LaRonde on Apr 29, 2008 at 4:29:28 pm
[Tom Westgate]"I watched Eran Stern's Invisible Cape tutorial which states it's a "simple method." However, to me, greenscreening your actor ahead of time isn't simple. It takes planning and preparation and equipment you may not have."
If that's the case, and you aspire to do effects work, I'd investigate another path in life.
Or perhaps you can just suck it up, acknowledge that shooting off the cuff is no way to get satisfactory effects, and start putting some thought into your shots. The people who accomplish the effects you want to emulate actually do that.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: A truly "simple" invisibilty effect? by Tom Westgate on Apr 29, 2008 at 5:15:45 pm
q[Dave LaRonde]"If that's the case, and you aspire to do effects work, I'd investigate another path in life.
Or perhaps you can just suck it up, acknowledge that shooting off the cuff is no way to get satisfactory effects, and start putting some thought into your shots. The people who accomplish the effects you want to emulate actually do that."
Re: A truly "simple" invisibilty effect? by Antony Buonomo on Apr 29, 2008 at 5:28:23 pm
Tom, it may seem hard to hear but I think Dave is more correct than not when talking about approaching a job professionally. Of course, if you're _not_ a professional and you have no/little interest in making it completely professional then yeah, other approaches will give you some kind of result; you'll learn something, your friends will think it's cool, the bluebirds will sing and there will be rainbows.
But if you want to be a pro, for the long term, he's right.
Re: A truly "simple" invisibilty effect? by Ron Lindeboom on Apr 29, 2008 at 5:40:19 pm
The truth is, if you fail to plan and plan well, you have, well ... planned to fail.
Sorry to use such an overused turn of phrase but it is quite true.
You cannot expect to emulate techniques that are drawn from well planned and storyboarded, orchestrated and executed shots that are the basis of the great shots.
Just last week, Kathlyn and I had to sit with a director we are working with who wanted to shot a scene wherein an old actor's hands get a close up and it's seen that he has had his fingers cut off while he was in a concentration camp. Well, the guy's hands are perfectly fine.
I had to explain to the guy that we needed to sketch out the shot. He thought it just happened by magic in post. I asked him, "How?" He couldn't answer and so I explained what it would take to shoot the shot with markers that could be tracked, what a clean plate is, how to track a shot and why, etc., etc. -- he had never done an effects shoot before (he's a pretty sober storyteller and doesn't do effects movies). When I was done explaining, he was pretty surprised. "That's a lot more work than I thought it was going to be," he said.
It always is.
Unless you want crappy results and are planning on failing.
Re: A truly "simple" invisibilty effect? by Tom Westgate on Apr 29, 2008 at 5:45:19 pm
Oh, I agree about planning and so forth. I guess since you all don't have all the background info, you are coming at this from the wrong angle.
Yes, I am a professional. I got my degree in 1993. I'm a corporate video producer. However, that is somewhat stifling creatively speaking. So, I have started a "film club" for actors and writers and crew to create our own passion projects on the weekends for film festival submission.
One overly zealous member came to me with preshot footage described in the original post. I'm just trying to help the kid out.
Re: A truly "simple" invisibilty effect? by Ron Lindeboom on Apr 29, 2008 at 6:27:18 pm
Thanks for the explanation, it is appreciated. Sometimes, the forum gets used by those who expect to come up with WETA/ILM "just add water" effects techniques by those who don't want to do any work to get there. (To be honest, for the ones reading this that know they do that, use the basics forum as we will extend a lot more latitude and liberty there than on this forum.)
Re: A truly "simple" invisibilty effect? by Dave LaRonde on Apr 29, 2008 at 6:31:17 pm
Thanks. The background helps.
Quite occasionally, we get high school kids who are convinced that possessing an HDV handycam, a laptop and Adobe Creative Suite qualifies them as the next George Lucas... and will not be dissuaded by mere advice.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
And yes, I'm still planning on doing it knowing full well that it's not going to look professional - learning experience and the whole bluebirds singing under rainbows thing.. :)
