Cracks and chasms don’t just fade, they drill right into the surface with brute force:

Grab an image with a chasm from a royalty-free page like sxc.hu or stockvault. In Photoshop, duplicate the background and remove the chasm, using the Clone Stamp Tool (S) in conjunction with the Patch Tool (J). This will be our clean plate.

To make the scene look more vivid we boosted the midtones and the red channel, cranked up the blue channel in the dark areas and turned the same channel down in the light areas to get some yellow in there. A vignette set to Linear Burn puts more emphasis on the spot where our chasm will appear.

Now that we have our clean plate and our backdrop in different layers, we hide the clean plate layer and save our .psd file.
Create a new Illustrator file and import the psd. Draw a single line describing the exact inner course of the chasm in a new layer.

Save the Illustrator file and open up After Effects. Import the Photoshop file, choose As Composition and Editable Layer Styles to keep our elements and color correction in extra layers.

Import the Illustrator file as well and open up the psd composition. Move the backdrop over the actual chasm.Double up the composition width in the composition settings (Command + K) and extend our setting by duplicating the backdrop layer and fading him with a feathered mask. We will need this set extension to have some additional space when we’ll create the final camera shake.

Drag the Illustrator line into your comp and apply an Invert effect to it so you can still see it on top of the chasm. In the switches palette, activate the Continuously Rasterize switch which is depicted by a little sun symbol. This will force After Effect to render the line as a perfect vector symbol irrespective of the layer’s scale value rather than rasterizing it before it’s even scaled.

Add a White Solid and apply a Linear Wipe Transition effect. Change its rotation value to -45 and animate the Transition Completion from 100 to 0 over 10 seconds. At 5 seconds, your layer should look like this:

This wipe will represent the growth of our mask revealing the chasm. Precomp and hide it before you rename it to ramp: chasm evolution. Hide the layer with the inverted line too and rename it to line of chasm. Now apply a Lens Blur filter to the line of chasm and change the Iris Shape to Octagon and the Iris Radius to 40. You will see the line being blurred out; in fact you won’t see much left of the line. That’s okay, since we will take control over the blur distribution in a minute. Change the Depth Map Layer from None to our layer called ramp: chasm evolution. As you can see, our line of chasm now adapts its blur to the actual value of the wipe.

The darker the pixels of the wipe get, the wider Lens Blur spreads out the line. In theory, this gives us the perfect wedge shape to create a realistic mask for the chasm. The problem we are dealing with now is the smooth, blurry alpha channel of our line. To counteract this fuzzy contour add a Levels filter and go to the Alpha channel. Set the Alpha Input White to a high value around 385 and the Alpha Output Black to a value around the 7400ies to solidify our line of chasm to a leech-shaped stroke:

This mask already looks pretty good, but we need to get rid of the lower part of the line looking like an umbilical cord wanting to get cut so the chasm won’t be visible from the first frame on. Use a Matte Chocker filter to remove the dispensable part by setting the Geometric Softness 1 to 8, Choke 1 to 50 and the Gray Level Softness 1 to 0%.
Use the line of chasm as Alpha Matte for the actual chasm and look at the result – we’re almost there!
Notice the whole animation is terribly slow, but we want to keep everything layed out and linear for fine-tuning, timing will be one of the last tasks we will take care of.
Now draw a shape (or create Solids and mask them) on each side of the chasm and check where your light is coming from. To enhance the realism, you want to colorize one with the brightest color you can pick from your underlying clean plate and the other one with the darkest color you’ll find. You’ll get something out similar to this:

As light is not just a plain shape but a widely spread array of nuances, we have to fade it smoothly. Do this by applying a Linear Wipe Transition with a Transition Completion value of about 50% to each the shadow and the light shape, one with 40° and the other one with -130° of Wipe Angle in this order.

Now copy the animated Linear Wipe Transition from our line of chasm and use it on both our light and shadow. Turn the opacity of light and shadow waaaay down, to a value around 8%. Our chasm is now set up and we can proceed by giving our shot the final touch. Place our composition in a new one, this time using the final proportions. Right-click on the layer with our complete composition and choose Time > Enable Time Remapping. Insert some keyframes and remap the timing until you get the feeling of a realistic crack. Usually, they grow rapidly and slow down pretty drastically every now, just to speed up again. Fool around.

Add an expression to both the rotation and position properties of the chasm-comp by clicking on their stopwatches while pressing the Alt-Key. Insert the following expressions:
wiggle(50, -3, 6); for the position and wiggle(10, -0.1, 0.1); for the rotation.
Bake the expressions via Animation > Keyframe Assistant > Convert Expressions to Keyframes and remove the keyframes outside the range in which our chasm opens up. We moved the first keyframes a bit back in time and the last ones a bit further so the fake camera shake won’t start too fast. If the expression is still running, turn it off by clicking on the small equality-sign next to the expression. Out position and rotation keyframes look akin to this:

To improve the effect even more, we added two small dust clouds we included in the final package. Create a new White Solid and apply a Radial Ramp to it, going from black to white. Move the black center to where you want the camera’s fake focus to be and Precomp the layer so we can work with the data we’ve got out of the ramp. Create a new Adjustment layer beneath the precomped radial gradient and apply a Lens Blur filter to it. Hide the radial ramp and use it as a Depth Map Layer on our Lens Blur. Adjust the other settings until you’re satisfied with the results. The only thing missing now are the sounds!

See our result on the top of this page or . the full package!

Jake & Dan

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