Join Lee Lanier for an in-depth discussion in this video Creating light effects, part of VFX Techniques: Crowd Replication with After Effects.
We used some various effects to create the sense that there is a floating projection above this man's head. Now it would be great to make it look like it's being projected from someplace with a beam, so it looks like it's passing through a say, a smoky atmosphere. We can do that with some effects in the Track Matte tool. Before I get to that, though, I want to briefly mention that I did renamed these layers here for organizational purposes, and I also renamed the motion trackers which you can do just by right-mouse clicking and then picking rename. So back to the projector, so I don't have a actual beam render, so what I will do is create a new solid and then Rotoscope that.
So this new solid, I'm going to call Projector, I want to make sure it's the same green, you can use the eyedropper to select and make it the Comp Size. We'll pull that below Banners, now it's really thick and opaque, so I'm going to reduce the opacity to 50%, and then in order to make it have a actual beam shape, I'm going to rotoscope with the Pen tool. I'm going to draw a box shape around the front and then make an end to the beam shape and then close it.
Now it would be nice to line this up or something in the background that could be a projector, and there are a bunch of little holes here in the concrete, so I can line up that point to one of those holes. The screen does change over time, so I do need to keyframe this, so in order to keyframe a mask to have a changed shape, I'm going to click on Time Icon beside Mask Path, you get the first keyframe there, and you can go to the very end, update the shape by clicking on the points and dragging them, that looks better there, and there it is second keyframe.
Now, it's all very hard edged mask, so what I can do is increase the feather to 20, and whenever you feather, it feathers it inwards and outwards so I need to also expand the Mask by 5 pixels, and there we go. Now we got a great beam shape, but this is going to be solid and not change over time, whereas a real projector will probably flicker. So to create the flicker, I'm going to use, a Fractal Noise in the Track Matte trick. So to create a Fractal Noise, I need a brand-new layer, and this fractal noise will take over this layer, I'm going to call this new solid Noise, and I'm worried about the color here.
So there's new Noise solid, I'm going to pull that right above Projector, and then we're going to apply Noise & Grain > Fractal Noise. That creates a noisy black and white pattern that's semi-random. I can use that to cut holes into the projector beam. If I go down to the Track Matte column beside Projector here, and change that to Luma Matte, what that does it cuts those kind of holes in that solid. It's those RGB values from the Noise layer and applies that to the Alpha in the Projector.
Now if you don't see a Track Matte column, just hit the Toggle Switches button. We can even improve it further by applying the same kind of noise to the video of the man speaking, so I'm going to copy this noise up, Edit > Duplicate, I'm going to place that above the green level of the man speaking, I'll turn off the color one for now, there's the green level. On the green level, I'm going to switch its Track Matte to also Luma Matte, and now there's holes in that. I don't have to live with those settings for that new Noise and go to that new Noise and change some of these values, for example, higher Contrast 160, I can change the Brightness 36 and then Scale underneath Transform to make the pattern larger, 280.
That looks better there. Now that pattern is not changing, so here what I can do is animate the evolution changing over time. Evolution figures out which slice of noise it takes from a three-dimensional pattern, so I can key the evolution on the frame zero at zero and go to last frame and give it three revolutions, and that will change the pattern over time. Now it would be great to get that same effect with the beam. So I'm going to go back to the noise being used for the beam, down here and alter these settings too. For instance, I may want the beam to be lower contrast, 25, not going to worry about the brightness here, but I also want it to change over time, so I'm going to key the Evolution on the first frame, go to last frame and then you give it more flicker by creating more revolutions by giving it 6 here.
So now if I play this back, I'm going to get a subtle variation in noise pattern making a flicker over time. Now the color version of the man speaking is turned off, I'll turned that back on. Now one last thing to be cool in terms of the projection field would be to maybe make some distortion in it. I can distort the green level over the top of the colored one, so it looks like just some bad reception, like they don't quite match up. So with the ProjectorGreen layer selected, I'm going to go up to Effect and try New Effect > Distorts > Turbulent Displace.
You'll see it distorts that green layer right away. Now I can also alter this. I can make it less strong by lowering the Amount to 4. I can change the Size of the noise that drives the distortion to 150, make a bigger noise pattern, you can also animate it over time shifting, it's very much like the fractal noise. So I'll key it at zero for frame one, go to the last frame, and maybe give this three revolutions. So, it's going to distort it, and it's going to make the green layer not quite match the color layer and look like some bad reception.
If you watch his shoulder, you'll see that distortion shifting over time, so it looks pretty good. Now one last thing we could do to this whole set up here is maybe give the sense that the beam at the origin is a little bit brighter. So there is a effect I can use for that, Light Rays. In order to apply it, though, I need to nest this composition. So I want to make a new composition, I'll call this AddCrowd, because eventually, we will add the crowd to this one, I'm going to go back and nest SetDress into this one and then apply the Generate > CC Light Rays effect, so it will create a little light burst where the center is, and there is an interactive Center tool here.
So I can place it at that circle on the wall. You'll see it creates a little light burst. I need to animate that center to put it where I want it over time, so here's the first frame, and maybe here's the last frame, and then I can adjust the radius which is the width of the burst, I'll make it smaller, 17, and then I can alter the intensity, brighter or darker. In fact, I'm going to key the intensity over time, so here's intensity, I'll turn on the keyframe there just make it go up and down kind of randomly, I'm not really concerned about the exact values, just want some randomness.
To get enough keyframes, I can go and copy these just select them Edit > Copy, and then paste, Edit > Paste, and I can grab random chunks of keyframes and do the same thing, so I'll have the entire timeline filed up with keyframes. Okay, so there's some random intensity change. Let's play back a little bit of this, so now we have the sense that there is a lens in the wall because of the CC Light Rays Effect, also we're getting distortion and opacity flicker through Track Matte, a Fractal Noise and also Turbulent Displace.
This pretty much wraps up everything we need to do for the Set Dressing, and now we're ready to start adding the actual crowd.
- Setting up your project
- Removing camera jitter
- Motion tracking CG renders
- Creating light effects
- Keying with Keylight
- Solving bad matte edges
- Rotoscoping green screen footage
- Color grading to match elements
- Relighting the scene