How to: Animate a dance-off for a music video in After Effects
- 09 February, 2010 14:26
In this tutorial we’re going to create an animated echo effect, not using the built-in Echo filter, but taking advantage of transparency mattes from keyed footage. You can grab one of the free clips on Ribbit Films' website.
As well as the standard effect we’ll learn how to use the techniques to add sparkle to your compositions with particle effects and colour blending modes. Ideal for your own retro pop video, you could also use this in product promos or portfolio pieces, so let’s get started.
Step 1 Set up a new After Effects project and import a clip downloaded from Ribbit Films' site. If you’d prefer to use your own clip, make sure you can establish an alpha channel by shooting against a greenscreen and using the keying tools within After Effects. The end result should be a strong silhouette in alpha. How much detail you retain in the clip is personal choice.
Create a new composition in the size you want your final piece to be. We’ve opted for 720p here, at 30 frames per second because the clip we’re using is 30fps and we wanted to take advantage of the high-quality clip from Ribbit Films. Use whichever settings suit your project. For this tutorial we’ve set the comp to be 30 seconds long.
Step 3 Drag the dancer clip into the comp. Scrub through the timeline to check out the moves. If your clip is longer than the comp, as it is in this case, you can reposition the clip by clicking and dragging to the left in the layer panel. Find a portion of the clip that works for you.
Create a new black solid (New > Solid) and choose to make it the same as the comp size. Drag the solid to the bottom of the layer stack so that it sits behind the dancer.
Add a new yellow solid and position it at the bottom of the layer stack. Draw a rectangular mask over the top two-thirds of the frame and add a feather to the mask by opening the disclosure arrows to reveal the mask properties. To position your dancer on the stage you’ve just created, simply click on her and drag her within the composition window.
There’s a small amount of fringing intermittently throughout the clip around the feet area. You could tidy this up by using a couple of effects in After Effects’ tools, which you’ll learn how to do later.
Duplicate the dancer clip layer by highlighting it and pressing Ctrl/Cmd + D. A second copy of the layer will appear. Turn off the visibility of this layer and drag it beneath the original dancer clip. Add a new solid in a bright colour (we’ve used orange). Drag this beneath the copy dancer layer and set the track matte to use the duplicate dancer layer as a transparency matte.
Although this is working, you can’t readily see the results of your labour yet because the original dancer clip is obscuring the orange silhouette we’ve created. To deal with this issue, and to create the echo effect we’re after, click and drag on the duplicate dancer layer to offset it in time around 0.3 seconds. Experiment to get this completely right on a clip by clip basis.
View a RAM preview by pressing 0 on your keypad and you should now see the basis of the effect in action – each move the dancer makes is echoed a fraction of a second later by a bright orange silhouette. We can improve on this basic implementation and give it a bit more impact by playing with the scale and properties of the echo.
Add the transform effect to the duplicated dancer layer that’s acting as the matte for the red solid layer. By default, this effect does nothing, but it offers us several keyframable properties to play with. The option we’re interested in is scale. Use the Pan Behind tool to reposition the Anchor Point to the bottom of the feet, then starting at 100% and around a second into the compositon, add a keyframe for the scale of the clip. Move one second down the timeline and set the scale to 106%.
You’ve now created a smooth animation in which the silhouette grows in size so that it’s a cartoonesque version of the original. You can repeat this entire process for a second and third copy of the original clip, with each one becoming a little bigger until you have a triplet of echoes. Each should be offset in time a little more than the previous one, thereby creating a wonderful multiple echo effect.
Now take it a little further. Using the same technique of alpha matte you can apply different effects to your solid layers to add internal movement to the silhouettes while retaining the overall outside shape of the animated dancer. The most obvious choice is to add a particle effect.
Create a new solid in a contrasting colour. Using the Pen tool drag some basic flower shapes. You don’t need to be accurate or aesthetically perfect here – quick and dirty will work just as well as precise. Pre-compose the layer (Layer > PreCompose) and drag it to the bottom of the stack, then hide by clicking on the layer eyeball.
Drag an instance of the CC Particle World particle effect onto one of the silhouette solids to create a basic particle effect. Set the particle type to Textured Faded Disc, then select the flower layer as the texture layer. Experiment with the physics properties and set the Particle Birth Rate at a reasonable number; we opted for 200.
View a RAM preview by pressing 0 on your keypad, and sit back and wait for a while as After Effects renders the Particle Effect.
You may see an improved performance by pre-composing the Particle Effect layer once you’ve added the CC Particle World Effect.
Finally, colour correct the dancer by adding a levels effect (Effect > Color Correction > Levels) and drag the white point to the left of the graph to create a brighter image over the dancer. Now add an additional black solid with a heavy feather over the bottom third of the comp to disguise the fringing.