Join Ran Ben Avraham for an in-depth discussion in this video Adding randomness to the stream, part of After Effects & Element 3D: Animating a Scene with Water.
- [Instructor] Our water stream behaves very nicely at this point, but once we'll start duplicating this layer, the water streams will look identical. And to avoid that, I would like to add some randomness to each water stream layer. To achieve that random look, we'll go back to our Emitter. We can close Physics, and go to Emitter. And we'll scroll down here. Over here, we have the Random Seed. And if we will slide this number, we can see we get different looks by simply changing the number.
I would like to insert an expression to this Random Seed, so I'll Alt + Click on the stopwatch. And in the Expression window, I'll write a wiggle expression, and end it with a semicolon. So what we got here is wiggle one time a second and 300 at any direction. So now we'll get a more of a natural look to our water stream.
Now we have to remember that this is one stream, and we are going to have a lot more streams in our scene. To avoid having them all look the same, we'll need to expand this expression. So let's see. I'll enter the expression again. And before the semicolon, after the brackets, I'll add plus index. Make sure to use lowercases all around or else your expression won't work.
Now when we write index, the index refers to the number of the layer. At the moment, this is layer number one and Element Null is number two, Element is number three, and Background Image is layer number four. Let's mark the Stream Row layer once again, and hit U twice to reveal the expression. Let's scroll down here. And to complete the expression, we'll add times five.
So that's wiggle, for one time a second, 300 in any direction, plus the layer index number, times five. Wonderful. Adding randomness to the particle's looking behavior is always a good idea as it adds more of natural look to our design, and that is especially true when we intend on using several similar particle systems in our scene.
This is a project-based learning experience. Each step of the process is rich with object lessons that are applicable to the variations that a motion design and compositing artist will face in the real world.
- Creating a showerhead 3D mesh
- Creating a single stream of water with a particle system
- Creating a full water stream
- Animating the scene camera
- Adding a background image
- Adding steam and haze
- Creating a depth-of-field camera
- Adding final compositing tweaks like light wrapping and grain