Compositing a Flood Effect in Apple Motion

Tutorial: Page (1) of 2 - 02/15/05

Compositing a Flood Effect in Apple Motion Combining filters and masks to create bodies of water By Dave Nagel Apple's Motion includes a number of particles and filters for creating fluid effects. But what it doesn't have is a one-step solution for generating a flood effect--taking a piece of footage and making it look as if a portion of the image is surrounded by a body of water. For that, you'll need to do some compositing. Here's how it works.

Before we get started, I should note that this technique will work on still images or motion footage taken with a fixed camera. If your camera is in motion, you're going to have to do some tracking in order to get this work, and, of course, Motion 1.0 doesn't have a built-in motion tracker. So for now, we'll stick with fixed-camera footage and still images. Also, this tutorial is not going to backpedal and explain every little thing (like how to add stops to a gradient). For these bits of information (and more), be sure to check out our past Motion tutorials, which you can find by clicking here.

For our effect, we're going to start with a piece of footage and add water to the scene to make it appear as if it's surrounded by a flood. Below you'll see some examples of the effect on various piece of footage.

And here's a sample of the effect in motion. (see the end of this article for more examples.)

It's a fairly simple and versatile effect, but one that does require several filters and masks to accomplish. But you can do it all with the tools that are built into Motion.

Step 1: The reflection layer
To begin, open up Motion and import your footage. Then make a duplicate of your footage. Create an upside-down mirror image of the duplicate footage by inserting a negative value in the Y Scale property in the Inspector.

Now add a rectangular mask to the mirror footage (using the rectangular mask tool), selecting the portions of the image you want to keep. (The top boundary of the mask should be at the point where you want the fictitious water line.) Then position the duplicate image so that it lines up with the original footage at the "water line." You may need to adjust the position of the mask to get it just right.

That's it for the reflection layer for now. We'll come back to it later to add effects and displacement.

Step 2: The first water layer
For the displacement of our reflection image, we need to create our first water layer. This layer will not be visible but will allow our reflection layer to "ripple" with our surface effect when we go in and add displacement.

To create this layer, go into Motion's Library called "Generators." Select the Cloud generator, and bring it into your composition. Then stretch it down so that it covers up your reflection layer. In the Inspector palette, set the Method for the noise to "Turbulent." For additional contrast in the cloud layer--which makes for better displacement--you'll also want to add in several several black and white stops in the Cloud generator's gradient, as seen below.

You'll also want to stretch out the image so that the clouds have more of a horizontal orientation (as seen in the image above).

Now, for our clouds to work effectively, we're also going to need to add a number of filters. A Directional Blur will help create better perspective for the image. Brightness, Color Emboss and Unsharp Mask will each help with the displacement we'll be trying to create. Rather than go through these each one at a time, here are the filters I've used on this image, along with the settings.

In addition, there's on optional filter you might want to use: Gradient Blur. This can help tone down the rippling effect in the distance by simply blurring the top portion of the Clouds layer, while leaving the bottom (closer) portion of the layer intact.

Page: 1 2 Next Page

Related Sites: Creative Mac , Digital Producer , Hollywood Industry , Digital Animators , Animation Artist , Siggraph News , Audio Video Producer , Digital Post Production , Film Imaging , Presentation Master , Oceania , MacAnimationPro , Motion , BN - NAB , BN - IBC
Related Newsletter: DMN Newsletter , Timeline Newsletter , Mac Alert Newsletter , Renders , KNews Newsletter , Digital Media Net , DMNForums , Tutorial Finder