Join Lee Lanier for an in-depth discussion in this video Animating engine flames, part of VFX Techniques: Space Scene 02: Compositing in After Effects.
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We broaden the shadow layer and also a special color render pass layer, to try adjust the specular quality. I mentioned, once you add that color layer, you probably want to adjust the red halo, in chip spec layer. I'll show you what I came up with very quickly and I'll leave that to you to adjust. For example, the red halo layer has animated curves, blurriness, and opacity. For example, on frame ten, opacity is 90 and the curves have a decent amount of contrast.
By 26, where we really see the specula highlight, the curves hasn't changed too much. But the blurriness is up to 36. And the opacity is down to 60, to try to minimize, it's just like too intense. So here the blurriness has actually increased from 25 to 36. Then by frame 70, where the ship is pretty much parked and the specular highlight is very small, the blurriness goes up to 48. The opacity shoots up to 100. And the curves has this bend in it to try to retrieve the highlight somewhat to make it a little bit larger.
In terms of the Spec layer, it's a bit more simple. It has the animated curves and opacity, so by the end frame here, around 70, the curves is pushed upwards to try to retrieve more of the highlights so it's more white. And the Opacity has shot up to 95. Whereas at a earlier frame like 26, the opacity is 83, a little bit lower here. And there's much more contrast in the curve in terms of that J shape. In any case, I'll leave that to you to fine tune those elements and to set your own keyframes.
The idea is to make sure that the specular highlight looks good throughout the timeline. Let's bring in our next layer. Next layer, or render path's going to be the flames. So back to projects. Back to the ship folder. File>Import File, this is in the flames folder. I'm going to drop that on top of red halo, below mat. So here are the flames for the engine and also the little navigational thrusters at the front. Let's go to frame 40 where we can really see them well and one problem with the flames is they cover up everything, so let's go ahead and change our blending mode to screen.
Now we can see the ship. Another problem is the flames are very hard-edged, they're just cones inside Maya, so, let's go back to our channel blur to fix that. Effect > Blur & Sharpen > Channel Blur. I'll pick a big number for alpha blurriness. And that softens the cone. So, this may lead to problems later on. When we put the ship back over the background, terms of a fuzzy edge for the entire ship. But we'll deal with that at a later point. For now, let's move on. Now I'm not crazy about the orangey color, so I can also change the color.
Let's go to Effect > Color Correction > Key Saturation. Here I'm going to spin the wheel and change the color until it gets to a more blueish cyan range. So 230 works pretty well. And then I'll increase the saturation to the maximum, 100. It'd be great to also get a glow here, so once again, Effect>Stylize>Glow and because the size of the engines changes in the distance than close up, I should animate these properties.
So I'm going to key Threshold, Radius and Intensity. And we'll try, for this frame, 60, a big radius, so it spreads out, 75, and a huge intensity of ten. So it's very intense. Now for an earlier frame like 25 I don't need that much. because the engines are so small. In fact, it starts looking kind of strange there. So, let's go down on the threshold. Now that actually makes more stuff glow. But then I can reduce the radius a bit.
But definitely, reducing intensity down to four, it makes it more reasonable. Now I don't really want the engines on the entire time. The story is, the ship flies in, stops, and then flies off. So we want to be able to turn the engines on or off. So a great way to do that is through a pass through animation. Now before we get to that, I really don't want the navigational thrusters here. We are going to save that for a separate layer where they will have their own animation, so we're going to cut those out for now, and the quickest way to do that is to draw a mask.
So with the flames layer selected, I'm going to go to the Pen tool and draw a rough square or rectangle around the engines, and that will separate them. You're going to have to key this over time. So go to your masks, click on the time icon beside mask path, go to other frames, and then update the mask shape. Now I'm only going to set a couple of frames here, just to save time. You'll need to spend a few minutes to go through the entire timeline and set a key every few frames.
At least when the engines are on. So very quickly, I'll set a few here. Once you get the mask, then you can start dealing with the opacity. So let's say that on frame 40, the engines are definitely on. So I'll key the opacity at 100% But then at 45, the pilots cut the engines, and they're off, zero. But by the time we get to frame 90, well, he's still sitting there. So the engines are still off. So I'm going to force the keyframe at zero. So I'm going to right mouse button click over Opacity and add keyframe.
But then in frame 95 he's back on again, 100%. So that's a pretty gradual on and off. What we can do instead, though, is flicker or sputter the engines. One way to do that is just to randomly change the values in between your current keyframes. So if I go to frame 42, I can suddenly drop the opacity to 25, but then say 44 or so, then shoot up the engines to 33. So that's a gradual sputter where it fluctuates instead of tapering in a linear fashion.
Now that's a more subtle one. If you want the sputter to be more intense, make a greater range of values. So if I go to frame 90, they're off, at zero. But then two frames later, I can shoot the opacity up to 75, but then shoot it back down to a low number, say 25. And then of course, at that point, they go back to being 100%. So it's more of an intense variation so you'll see more of a flicker there, or a sputter. Now you should experiment with those values and come up with your own variation there.
Now we can also flicker the engine when it's on in general, just so there's this subtle change as it's on. So one way to do that is to just randomly select values every frame. So maybe, on the first frame, it's 90. Then they go down to 75 on the frame after that. And after that, they get back up to 95. And then they go down to 16. So just random up down, up down, up down. The greater the difference in values, the greater the sputter and the flicker.
Once you have a chunk of keyframes, you can draw a marquee around them, turn them yellow, Cmd or Ctrl, copy them with the C key. And then paste them into empty areas. And you can just keep pasting, paste over old keyframes. You can even grab a larger chunk of keyframes now and copy those. Paste those in. And keep pasting until you've filled in that on area. You can do that here before frame 40, and also after frame 95. So if you want to see what this looks like in the Curve Editor, just click the Include This Property button.
Go to Curve Editor here and you can see that random fluctuation. And in fact, you can move keyframes around here if you want to. Just click them and then drag them. Now I'll leave the exact animation up to you. Again, experiment. But the goal is to get a flicker when the engine's on, and then a stutter or a sputter as they turn off and turn back on for a few frames. And of course you'll need to finish all the animation on the mask so that the engines are saved but the navigational thrusters are thrown away. So there's a brand new render pass. And we use some of our old tools like, Channel Blur and Glow, to add some variation.
And more importantly, we've added a mask, to separate out just one part of the layer, and throw away the rest.
- Setting up the project in After Effects
- Combining background elements
- Layering render passes
- Adapting stock footage
- Adding After Effects particles
- Color grading the composite
- Adding camera shake and grain