Simulate a Dramatic Underground Blast

Feb 18th in VFX by Fred McCoy

In this tutorial we learn how to harness the shatter plugin along with some expressions and color correction to simulate a dramatic underground explosion that ripples and dislodges the ground.

Author: Fred McCoy

Fred McCoy also known as Megalongcat is a Communication Design and Technology Major from Parsons School of Design in New York City. He currently works for the website design company Blue Fountain Media and runs the design criticism blog Megalongcat. His field of expertise includes Corporate Branding, SEO Design, Front-End Web Development, Design Research, Ethical Design, Motion Graphics and Design Critique.

Preview

RSS readers: click post title to view preview video at AETUTS.

1. Introduction

Hey everyone, this is my first tutorial on AETUTS but I can promise you that it will be a useful one. Today we're going to be learning three things: How to use the Shatter Effect for special effects, the Wiggle Expression, and Color Correction.

Requirements:

• Photoshop
• After Effects (7, CS3, or CS4)

2. Picking Your Image

So what's the first thing that we need to do? We need to get an image. The one I chose is an empty desert with a road leading to the horizon line. This is ideal for the earthquake effect we will be creating. I found mine on www.sxc.hu but you can use almost any image that has a road leading to a horizon line (a picture of Broadway in NYC for example).

3. Stepping into After Effects

Open After Effects and create a New Project File > New Project and double click inside the empty space where your imported files would normally be to pull up the import menu. Navigate to the picture you've chosen make new project. Instead of creating a new composition the normal way, drag the icon of your imported file over the composition icon at the bottom of the create a new composition box to create a new composition the size of your image.

4. Setting up the Comp

Now why did we make such a large composition? (My image is 630px x 800px). Well that's because we're going to need a composition larger than the final render size to animate it properly. This will make more sense later. Go to Composition > Composition Settings (CTRL + K / CMD + K) and set the length to 10 seconds.

5. Setting up the Timeline

Make a duplicate layer from your image. Select the layer and press CTRL + D or CMD + D to expedite the process and move your timeline selector about 7.5 seconds into the composition's timeline.

6. Setting up a Mask

It's time to make a mask! Select the top most layer and select the square tool/pen tool and mark off the road on your canvas so that it's the only part of the image that shows up. To see if this is working make sure to turn off the bottom layer.

7. Editing the Mask.

If you made a square mask, edit the points of the mask by double clicking the mask and selecting the corner points if you used the square tool so that it becomes the shape of the road and stop the mask where the road touches the horizon line. Add a mask feather while your at it by selecting the layer with the mask and hitting the m key to bring up the drop down menu, to open up the mask feather section you need to click the little sideways arrow twice to bring up all the mask options which has mask feather, mask size, etc. Set the feather to about 111px. You'll probably have to adjust this later so any amount is fine for now.

8. Shatter Time.

Onto fun steps, it's Shatter time! I'm going to divide the shatter effect into two parts so I can explain what I'm doing in detail: Forces & Physics. So select the top most layer and go to Effects > Simulation > SHATTER. It will put your composition to look like a wireframe image. Don't worry, that's a good thing. After Effects offers the wireframe preview because it's a RAM intensive rendering process so it's easier to preview the effect this way.

9. Shatter Shape.

Select the drop down menu for SHAPE and change the pattern to glass , change the Repetitions to 78. Repetitions is the number of breaks in the glass. The more repetitions the finer the glass pieces that actually shatter. Less repetitions, the larger the pieces. Leave the Direction (where the shatter goes), Origin (Where the shatter starts), and extrusion depth (thickness of the shatter pieces) alone for now.

10. Shatter Forces.

Open up the drop down menu for Force 1 . Now notice in the final product video, the shatter starts at the bottom of our screen. So lets select position by clicking the little crosshair next to the word and place it at the bottom center of your composition. There's no need to set the keyframe.

11. More Shatter Forces.

Click the keyframe button (the little stopwatch) next RADIUS and then go back in your timeline to about 2.25 seconds and hit the keyframe button again, but this time change the radius from it's default size to 0.00 Now if you scrub through your timeline it should look like it's exploding. Go to 10 seconds in your timeline and change the radius to 1.20. Lastly, change the depth to .60

12. Shatter Physics

Physics Time! Go down to the physics tab and use the settings in the screenshot. Rotation speed = .20, leave tumble axis set to none , set your randomness to 1.00 and leave viscosity at 1.00. Set the Mass Variance to 30%.

13. More Shatter Physics.

Gravity time. We're still in the physics tab but gravity deserves its own explanation. Go back to 7.5 seconds into your timeline and change the gravity to 10(max) and hit the keyframe button. Go to the end of your timeline and set the gravity to 0.00(minimum). You can do a quick render to see what it looks like so far. How does gravity work? Well 0 means there is no gravity which means things will float to the top of your screen indefinitely, and 50 means that things will fall indefinitely. We have it going from 50 - 0 to make it look like the shatter effect is moving up your screen. I had to adjust the number of repetitions to 48 to make it look less repetitive. I also changed the extrusion depth to .5 to give the shattered pieces a little more depth.

14. Image Color Levels.

Press CTRL+D on the top level layer and then select the middle layer (your original desert layer with the shatter effect on it) and delete the shatter effect. Then go to Effect > Color Correction > Levels an change the Input Black to 82.0. this will give the dirt floor beneath your shatter effect a different color so you can tell there's something underneath it.

15. First Render

Export your composition. Go to Composition > Add to Render Queue. Select lossless and change the format to Quicktime Movie and click format options and then change the render codec to .H264. Make sure audio output is unchecked and hit okay and render.

16. Setting up the New Comp.

Import your newly exported quicktime movie back into after effects and drag it onto the composition icon to turn it into its own composition. Open up the composition settings again and select NTSC as the preset and hit okay.

17. Color Correction - Blurring.

Hardcore color correction time. Duplicate the layer and change the blending mode to Multiply then go to Effects > Blur & Sharpen > Gaussian Blur and change it to 6.6

18. Color Correction - Tint.

Duplicate the layer one last time and go to Effect > Color Correction >Tint. Map the black to FFB400 and map the white to FFDAA6 .

19. Final Animation.

Select all the layers and move them down so that the sky is touching the top of the composition. Go to the end of your timeline and hit the p key on your keyboard to pull put each layers position and add a keyframe by hitting the stopwatch keyframe button (this will add keyframes for all layers). Go back to the beginning of your timeline and move all three layers up so that the bottom of the image is touching the bottom of the composition canvas. Any changes will automatically set keyframes for you. If you scroll through your timeline it should look as though the image is moving up the screen from the bottom of the picture to the top.

20. Fixing Our Sky's Tint.

Select the top most layer and add a mask using the pen tool and draw around the sky so that your TINT effect only applies to that area. And add mask feather of 50 pixels and render out the entire scene.

21. Conclusion Step - Expressions.

Onto the final steps. Repeat step 16 and select the only layer on your timeline and hit the p key to bring up its position. Hold the alt key and click on the keyframe icon(stopwatch) and a weird input field will come up. This is the expression field where you can type code and get After Effects to do all kinds of weird stuff. In the expression box, type wiggle (10,3,10) without the quotes and click outside of the box. If your screen doesn't show a render, hit the caps-lock key. Viola! Play around with the three numbers in the code to get the desired effect you need. You might have to shrink the composition size so that no black area shows. Render out your scene and you now have your own animated earthquake made from the shatter effecspamt. Hope you enjoyed the tutorial!