Particle exercise: Creating an impact splash
Video: Particle exercise: Creating an impact splashParticle exercise: Creating an impact splash provides you with in-depth training on 3D + Animation. Taught by Rob Garrott as part of the CINEMA 4D Essentials 9: Particles and Dynamics
- Final thoughts
Particle exercise: Creating an impact splash provides you with in-depth training on 3D + Animation. Taught by Rob Garrott as part of the CINEMA 4D Essentials 9: Particles and Dynamics
CINEMA 4D Essentials with Rob Garrott is a graduated introduction to this complex 3D modeling, rendering, and animation program, which breaks down into installments that can be completed within 2 hours. In this installment, Rob introduces particles, a cluster of objects used to simulate effects like snow, sparks, fog, or fire, and dynamics, which allow you to define how objects interact with their environment. The course covers creating a splash effect with particles, working with more advanced Thinking Particles, and how to understand the difference between the dynamics system's rigid bodies and soft bodies.
- Working with particle forces and the Emitter object
- Using Thinking Particles with the MoGraph Tracer
- Understanding the Dynamics engine
- Combining Thinking Particles with Dynamics
- Creating dangling objects with spline dynamics
Particle exercise: Creating an impact splash
For this example, we're going to create a splash of particles. I have a sphere hitting the floor and melting into a flat object, and this was created in an earlier module, under Deformers, and it's basically just a sphere that is being influenced by Melt Deformer. And the Melt Deformer is causing it to actually splat out when it hits the ground. So what we want to do is to create some little globs that will come of this location when the object hits the ground. So the first thing we need to do is create an Emitter Object. So let's go to the Simulate Menu, and then go to Particles, and go to Emitter.
The Emitter is going to splash out particles, and we want it to spray it up. Remember, the Emitter spits out along its Z-axis. So let's rotate it. I'll hit R on the keyboard. I'll hold down the Shift key to do it in even increments. And let's rotate it up 90 degrees. Now let's rewind and hit Play. So the particles are coming out a bit little soon. We actually don't want the particles to actually come out until the sphere hits the floor. So right about there, which is frame 11. So let's go to our Emitter Object and change, under the Particle Options, the Start Emission to be frame 11.
Now let's change the Stop Emission from 150 down to, say, 20. Then we'll change the Birthrate in Editor. Let's make this up pretty high, let's call it, say, 50 x 50. And then when we rewind to 0, let's hit Play. Boom. Not bad. I think that's still not quite enough particles. Let's change that from 50 to, say, 200 x 200. Let's rewind back to 0 and hit Play. Boom. That's better. The particles, when they come out, you'll see that they're actually emitting.
Let's rewind back to 0 and I'll scrub through this. You can see that they're coming out and they're not spraying outward. We want them to spray outward in all directions except for down. Let's zoom in on this a little bit more. Under the Emitter Properties let's change the Angle Horizontal. The Angle Horizontal is the angle around the Emitter's Y-axis. So let's change that to 180, actually a little bit less than 180, let's call it 170. And let's change the Angle Vertical, that's the vertical is around the Z-axis, to 180.
And you can see the Angle Vertical tops out. When we rewind back to 0 and hit Play, you'll see that our objects are spraying out. You'll notice that they're not spraying below the ground, they're going upward. The other thing you'll notice is that the Emitter is a little bit big compared to the splats. So let's go over to the Emitter Size and bring that down to, say, 70 x 70. That's going to tighten up our spray. Let's rewind back to 0 and hit Play. There we go. The next thing we want to do is to have the particles fall downward after they come out of the Emitter.
Right now they come out to the Emitter and go off in whatever direction they started in. So let's go to the Simulate Menu and go to Particles again. Let's add in Gravity. Now when we rewind and hit Play, our objects fall down. They splat outward, and then they fall down. Let's rewind back to 0. Now our particles aren't making it very far up into the air, before they are splashed down. So let's go back to the Emitter and adjust the Speed. If I go the Particle Option and change the Speed from 150 to say, let's try 300.
Rewind back to 0 and hit Play. Not bad. So you can see they're still not making it very far up into the air. So let's crank the Speed up just a little bit more, let's try 500. Rewind back to 0. And that makes the splashes a little bit too big. Let's rewind back again and bring that back down to 300. I think what the problem is also is that the splashes are lasting a little bit too long. Right now, they live all the way to 600 frames. Let's have them live only about -- let's call it 30 frames.
Let's change that to 30, and then rewind back to 0. You notice, I'm rewinding and hitting Play each time I make a change. Much better. In order to get a feel for what our splash is actually is going to do, we need to be able to see the actual particles. Right now, we're seeing a representation of the particles. We're going to spit out spheres, and let's add a Sphere to the scene. The Sphere is really large, let's scale it way down, let's change the Radius to, say, 5. That's a little bit too small.
Let's make it about 8. I think it's better. Then we want to change the Segments to 6. There's an interesting feature on the sphere, this Render Perfect. We can render this down to 6, and even though we such a low polygon count, when we render, Cmd+R, it still renders to a perfect sphere. Let's hit A on the keyboard. So now let's make this Sphere a child of the Emitter Object, and select the Emitter, and then we're going to tell it to Show Objects. Now rewind back to 0 and hit Play.
You can see there are our particles jumping out. The particles are all living the same amount of time. Let's introduce some Variation in the Particle Lifetime. Let's bring that up to 100, and rewind back to 0. You can see that now, they'll die off at a slightly different rate. Some die off sooner and some die off longer. Now what we want to do is change the End Scale. We want our particle droplets to hit the ground, splash, and then radiate outward and diminish as they live.
So let's change the End Scale down to 0. So now, over the course of the Lifetime, they're going to scale down. And then, let's introduce just a little bit of Variation in that. Let's rewind back to 0 and hit Play. And that's starting to feel a little bit more like a splash. The next thing we need to do, you'll notice if I hit Play, I'm going to orbit around, so I'm kind of even. I'm very close to the ground now looking at it sideways. We don't want any of our particles to go down below the ground. We want them to splash outward and then bounce across the ground.
So let's go to the Simulate Menu, and under Particles, let's add in a Deflector. The Deflector Object comes in pointing along the Z-axis. So let's rotate it around. Hit R on the keyboard to bring up the Rotation Tool if it's not already active. And then rotate this around. Let's hold down the Shift key so we do it in even increments. So now we're at 90 degrees. Now let's make the Deflector Object really, really big. So go to the Deflector, under the Object Properties, and make the Size, let's make it huge. 10000 x 10000.
Now there's no chance that our particles can fall below that. Let's rewind back to 0 and hit Play. You can see that they now are being deflected off the floor. They'll skid away into the distance. The Bounce on it, let's reduce the Bounce from, say, 100 to about 60 or so, so that our particles don't tend to bounce up into the air quite as much. There we go. I think we're about ready for the last step.
These particles, when they spit out, are just spheres. We want to create a little blobby mass that spits out of our object, and we're going to use something called a Metaball Object to do that. Underneath the Modeling objects is this little guy right here, and it's got a kind of a blobby icon for it. This is a Generator Object that takes any kind of spheres you place under it, or Splines, and creates a smooth skin based on the positions and sizes of those shapes. Let's move the interface down a bit so we can see all the hierarchy. And twirl that close. Let's drag the Metaball down and make the Emitter a child of the Metaball Object.
Now what happens is, we get this weird looking blob here. Let's rewind back to 0 and scrub forward in time. This doesn't look like a splash at all. What's happening is that the Metaball Object has some settings on it. Number one is the Hull Value. The Hull Value determines how accurately the Metaball will conform to the shapes that it encounters. So let's take the Hull Value and drag it up. It's a little bit counterintuitive to what you might think. Let's back up to time 0 and scrub forward to the splat where the particles are coming out.
Now what we want to do is to decrease the Editor Subdivision. The Editor Subdivisions are showing some very coarse representation here. So 40 centimeters is a really low resolution, so let's increase the resolution. That's very important, never drag the Editor Subdivision below the Render Subdivision, you might get a crash. Let's bring this down to, say, 10. And so you can see, now it starts to look a little bit more like a blob. Let's bring this down to 5, just like it is in the Render. And you can see that's looking much better.
Let's go to the Hull Value and increase it, so that we have a really tight representation. Now when we scrub through, boom. You see we get the splashes radiating outward. And the cool thing is that they die off right when they're supposed to. So let's rewind back to 0 and hit Play. And I think we're getting a really good splash going out of this. Let's make the splash the same color as the splat itself, and let's drag the material up on the Metaball Object. I'll deselect the Metaball, let's rewind back to 0 and hit Play.
In order to get a feel for how this is going to look when it renders, let's hit Shift+R on the keyboard. You see our objects are still a little bit chunky. We might need to lower the values in both the Editor and Renderer Subdivisions. So let's close that up. And then under the Metaball Object, let's take these both down. I'll start off by changing the Render Subdivision down from 5 to, say, let's call it 2. And then I'll back up and make the Editor Subdivision 2 as well.
And you can see now that makes them a lot more accurate. Rewind back to 0, hit Play, and now let's render that, Shift+R. And you'll see that those are much, much, more smooth. To make sure that we're actually seeing everything correctly, let's do a Preview movie. I'll deselect the Metaball and then hit Option+B or Alt+B on the keyboard. Let's change this from Full Render to Software Preview, and then leave the Size at 640, and hit Enter.
And it's going to calculate that Preview. And now in the Preview movie, we can see what our splash is actually doing. It's a little bit off center, but that's okay, you get the idea. It's caching the frames right now. When it's done caching, the line will be solid green, and now we're seeing the actual speed of Playback. That's a really simple example of how to use the Particle Emitter to create an effect. Go back and play with this setting. Add in Particle Forces, mess around with it, and see what kind of other results you can come up with.
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