Explosions

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Flash FX by AEJuice has hundreds of hand-drawn 2D FX elements. Works in After Effects, Premiere Pro, DaVinci Resolve, Final Cut, CapCut and more.

Four elements constitute an explosion:
1) The Initial Blast
2) The Smoke
3) The Fire
4) The Debris

The fire and debris are optional, what if it's only a fast and sudden puff of smoke? Batman's gas pellets from his utility belt just burst out quickly in high volume, with no heat, fire or shrapnel, but it can still be considered to be a small explosion. So these aren't hard and fast rules, but we'll try to cover these four points, there are many types of explosions, we'll go over a few in this post, more different types and styles of fire, gas and water explosions in a few weeks.

First thing... RESEARCH

This is just a few of hundreds of great quality video you can use to study and reference. I can't stress enough how important research is in understanding the physics behind animated elements such as smoke, water, fire and countless of other effects-related scenes you may encounter. Observe how the initial blast bursts out the dissipation of the smoke all the dozens of elements to keep in mind, the flow and direction and swirling properties in certain areas versus others.

See more great slow-motion photography here.
Research, observation, practice, and planning are the number one rule for ALL animators.

Step one - The Initial Blast






Michel Gagné, is one of the modern day 2D FX masters. Here's just some his Effects Designs for the Clone Wars Animated Television Series:






















RESEARCH, RESEARCH, RESEARCH.
Always find as much research as possible.
The very first thing that CG animators for feature films do once they receive their layouts is seek out reference materials. Find and study footage relevant to your shot, then start planning out the shape, volume, position, and timing of your effects.

A last footnote regarding cleaning up your final lines... Cartoonist Bob Flynn shows here on his blog how to clean-up comics in Flash. These techniques most definitely applies to FX linework as well, though most effects animation is self-traced (colored outlines) being careful with your inked lines and how to tapper and thicken your brush-lines can go a long way in improving the quality of the final lines, here's an excerpt:
Step two - The Smoke

Right after the flash, the smoke takes over. It shoots outward fast and then slows down hard, so give it a strong ease out: big jumps between the first few drawings, tiny ones at the end. Think of it as volumes rolling over themselves, not as an outline that grows. As it slows, let the big shapes break up into smaller puffs and thin out at the edges. Smoke hangs around far longer than the fire does, so it is usually the last thing on screen.

Step three - The Fire

The fire lives inside the smoke for a short moment. Keep it fast and flickery, changing shapes every one or two frames, with tongues of flame licking upward out of the smoke. It burns out quickly, and the smoke swallows it, often turning darker as it does.

Step four - The Debris

Debris is pure physics: every piece follows an arc. It is fastest right at the blast, slows at the top of its path and speeds up again as it falls. Small pieces travel farther and faster than big ones, and a few spinning chunks with short trail lines sell the speed. Let some pieces bounce or skid when they land, that secondary action is what makes the explosion feel heavy.

Put the four together, blast, smoke, fire and debris, offset in time so they don't all peak on the same frame, and you have an explosion that reads in an instant.