Recently I was asked to create to animate water splashing from out from the wheel of a moving car, as if it was driving through a puddle. I studied animation at university, so I can say with some small amount of authority that animating water is generally considered one of the more difficult things an animator can do.

Probably the easiest way to solve the problem is to use video of water with a transparent background that has been modelled in a 3D application.

I used a video from iStock similar to this one:

http://www.istockphoto.com/stock-video-8526304-water-splashes-in-slow-motion-preview-darker-than-original.php

it didn’t have the perfect splash I needed, but there were enough different types of splashes and angles to be able to piece something together with multiple layers and some After Effects trickery.

The biggest problem I encountered was that iStock footage uses Quick Time with Photo JPEG compression which doesn’t have an alpha channel. You can however still create an alpha channel using a “luma track matte”, as this tutorial shows. A luma track matte is basically where After Effects creates an alpha channel based on luminosity while keeping the integrity of the original footage.

Check out the video tutorial here:

http://vimeo.com/7385956