Learn about adding a custom 2d particle emitter that emulates dust.
- [Instructor] We've seen how we can add Boris particle effects to recreate something very specific, like rain. However, you can also create a more generic particle system then fine tune it to make it look like something much more custom. For example, let's say I wanted to add more dust to this shot of the shovel, maybe as the shovel digs, there's a cloud of dust here. I can use a particle system to generate that and make it look like it belongs in the original shot. Let's give it a try. I'm back to the shot where the rain is added, and this is saved out as 6_2.
I'm going to start by adding a new solid to which I'll add some new particles. Color doesn't matter. I will make it the comp size though. And we'll drag that down to the center of the layer outline. To this I'll add a new effect, this time Particles, Particle System. Looks like it doesn't do much at the start, but if I play it back I'll see a burst of purple particles, and the color comes from the solid color.
What can we do with that? Well, I'm going to start by changing where the particles are generated. The emitter is something called the Center XY. I'll go to the first frame and move that down to where the shovel is and animate that. Now you notice that there's no particles at the start, but we'll deal with that in a moment. So the Center XY is right here under Production, and then I'll keyframe that and make sure it follows over time.
Alright, so there are some keyframes. There are the keyframes there, and it follows along. Now in terms of the particles not being there to start, it's because they have to be born, and by default they're born on Frame 1 and start to appear. However, I can go down to the bottom where it says Animation and change the Start on Frame to a negative number. So that's kind of like pre-roll. So now they start at negative 25, and by the time I do see the first frame they'll be in the shot already.
Let's look at some of the properties that effect how the particles are born and how they live and so on. At the top there is a Birth Rate. This is how many particles you get as the timeline plays forward. If I reduce this I get fewer particles. In fact, I'll go down to 10 because I want to make them larger I don't need so many in the shot. Life Span effects how long they live. If there's a short Life Span, they'll die and pop off and disappear at the end of that time. I want to make this a large number like 100 so they last longer than the timeline, and therefore they don't disappear.
Now they are moving downwards because there are built in forces that effect the motion. Before I get to that though I want to take a look at the Initial Velocity. This is the initial speed when they're born. I think they're moving too fast, so I'm going to reduce this to 25. Now in terms of the Gravity I can go find that also. This is underneath Movement, and there's Gravity. Now initially Gravity is like gravity on the Earth that pulls downwards, but if I change the Gravity Angle to zero it'll float upwards.
I can also reduce the strength of the gravity so they move more slowly, let's say 10. Now, I still think they're moving too fast, so I'm going to use another built in force which is Air Resistance. This is like friction in the air. I'll increase this to 50, and now they'll be more lazy as they move up through the scene. That's starting to look like perhaps a cloud of dust. Let's deal with the way they look next.
They're still purple and very small. Under Appearance we can find the color. There's a start color, mid color, and end color, so let's change color as they age towards their Life Span. I'm not going to use the mid color, but I will use the start color. I'm going to change that menu to Custom Color and select a dark tan from the background. In terms of the end color I'm going to change that to Custom Color also and make that the color of the sky so that as they float towards the sky they start to disappear just because of the color.
You can see the color variation now. They're very small though. I want to make them larger so they start to clump together into a mass. There's a Start Size and the End Size. Alright, that's starting to look more like a cloud of dust. Now at the moment they're rising up very much in a single column. I'd like to maybe make them branch, give them more variation as they flow upwards.
There are built in attractors, and attractors pull the particles towards themselves. Here are the attractors, and you get two by default, and these have center handles in the scene, although they look like other handles. So what you can do is grab these targets, Attractor 1 target. I'll place one of these on the left of the column and the second one on the right and make them pull the particles in different directions. Now initially they're not working because the power is off.
However, I can pull the power up. Here's the power for one. See how they pull the particles over? You don't want it too strong, just enough to branch. And here's the second power. Again, not too overly strong. You can animate these properties over time. You can animate the location of the attractors changing over time if you want to. You can play that back. So now they start to split off.
It could mean my first attractor is still too strong. Let's try that. Alright, so more variation in the motion. Now they're still very much particle like. I can see each individual sphere pretty much. (mumbles) stuck on top, so what can we do about that? Well, even if you adjust all the properties in the effect it still might not look totally realistic, so the trick is to add additional effects to fine tune them. For example, I can add a blur effect to that layer.
I'll grab a gaussian blur this time, the Boris one, and increase the blur so it looks more like a mass of dust or smoke. I'll try 100 here. And then I can also reduce the opacity of the layer. I'm going to go way down, let's say 40. I want them to be barely visible so I can't tell where my dust starts and where the dust from the original footage starts. We'll play it back.
So now the foreground is much dustier. It's like there's dust rising off the shovel. It's hard to tell what I've added here, which is great, but if I want to see a difference I can simply turn on or off the layer. Here's with my new dust on, here's off. Off, definitely the foreground is more clear, on, dustier. So we've used a generic particle system to create some custom dust. You have a lot of flexibility with these systems, and when you combine that with some other effects, like the blur, you can really make something that integrates well into your original shot.
VFX expert Lee Lanier begins by exploring shared Boris Continuum controls, and then shows how to apply stylistic effects. He explains how to work with the PixelChooser and Boris Lights, and discusses how to color grade and warp footage. He also takes you through using the Boris Chroma Key Studio and working with Mocha Pro for motion tracking, as well as how to add particles and work with 3D text.
- Overview of Boris Continuum
- After Effects preferences
- Applying stylistic effects
- Relighting with Boris Lights
- Adjusting colors
- Changing the time of day
- Warping footage
- Keying green screen
- Motion tracking
- Adding particles
- Working with 3D text