Fire, smoke, water and electricity... What animation would be complete without some elemental blasts, puffs and explosions!? These moments of magic are a visual feast, but they can be an animators worst nightmare.
These elements shift and distort their shape in a fluid and organic behaviour, which can be hard to emulate. This blog will break down a basic smoke technique in After Effects, which can also apply to other elemental materials.
There are a limitless number of tools within After Effects to create smoke in a range of styles. One of my favourite types to animate, is a 2D smoke that has a cel-animated or hand drawn quality to it. This traditionally would be animated frame by frame by cel-animators, but there are a few nifty after-effects tricks to emulate the style in half the time.
Take a look at the bubbling cauldron below which we will be recreating. There are two types of smoke at play here; the smaller and faster 'puffs' of smoke, and a bolder vector-like cloud.
Creating the smoke particle
The first stage to creating your smoke effect is to draw out a path for your smoke particle. This can be done using the ellipse tool within Adobe Illustrator. Remember that smoke is never symmetrical, and it doesn’t move in a linear fashion. With this in mind when we draw our particle, we should add additional anchor points and create some shape variation.
Once you have your particle, create a new shape layer in After Effects, and select path from the add menu. Next, copy and paste your particle drawing directly from illustrator into the path field in After Effects. For visibility, you will need to add a fill to the shape layer.
If we study a smoke reference, we'll see it expand and densen from it's source, then swirl, rise and disperse until we can no longer see it. To illustrate this effectively and avoid the smoke looking rigid, we will need to add some variation to the particle over time. To do this, we will need to set an end-state for the particle to morph into. Head back into illustrator and with the original particle path, manipulate it into an end state by moving the anchor points. You can be playful with this, but try not to cross anchor points over or this will cause problems with the morph effect.
Once you have your end state, copy the path once again into the After Effects shape layer, but this time at a new key-frame in the timeline. I suggest spreading the key-frames about 1 second apart. When you scrub through your timeline you will notice that the particle will now morph from the start state to the end state.
Presto, you've created a shape morph! Don't worry about it looking too clean or perfect at this stage, the end result will be much smoother. But it is a good idea to add some easing to the key-frames, to get some nice swing to the movement.
Animating the smoke particle
Now you have your smoke particle, set up a new composition and drag in your particle composition. Give it some position key-frames to animate it across the screen in the direction you want the smoke to flow. It is a good idea to align your position key-frames with your particle morph key-frames, so the smoke will morph in sync with the position change.
Once you are happy with your smoke movement, duplicate the layer and rotate it a few times to start building up a more complex shape. You can also move some of the duplicated layers a few frames forward in the timeline, to create a trail effect.
Adding Adjustment Layers
Adjustment layers are used to apply changes and effects to any layers that appear below it. You will need to insert an adjustment layer above all of the smoke layers in your composition, and then apply the ‘Simple Choker’ effect from your effects/presets menu. By increasing the choker, you will help to blend and soften the edges of the smoke layers beneath it, creating a more united smoke cloud.
Finally you'll need to add some shading to your smoke effect. Precompose all of the items in your composition, and then from the layer styles menu, add the inner-shadow effect. You can adjust the shadow colour to suit your preference. In the example below, I duplicated the composition and mirrored it beneath with a transparent fill, creating a shadow that emphasises perspective. And there you have it; a puff of smoke. You can play around with colours, opacity and layer styles to overlay onto your cauldron image.
Using trapcode for cartoon smoke
Now let's look at recreating the bolder mushroom-cloud that erupts from the cauldron. To achieve this effect, I used the plug in Trapcode Particular. This is a must-have tool for visual effects with potential for an endless variety of particle-based composites. In this instance, we will be using it to emit a 2D particle.
Start by creating a new composition that is 600 x 600 pixels. Draw out a circle using the ellipse tool and duplicate it. Give the top layer a black fill, and the bottom layer a white fill. With the lower layer, increase the size and offset it slightly, to create a shadow effect. It should look something like this:
Open a new 1920 x 1080 composition, and drag in the newly precomposed particle which will form the basis of this smoke effect. You will need to hide this layer, but we will revisit it later. Now from the layer menu, create a new solid, and apply the particular effect from your presets panel.
You’ll need to set the emitter type to box, the direction in the X axis to -90 and the particles per second to around 25. Next check the particle type is set to Sphere, and reduce the feather to 0. Increase the particle size until there are no gaps between them as you scrub along the timeline.
Applying these settings should give you something that looks like this:
Now we want to add some of the particles we created to this flat looking smoke effect. Duplicate the particular layer in your composition and in the effects settings, use the following steps:
- Change the Particles/Sec to 1
- Use the Position XY slider to move the emitter to left side of the layer beneath it
- Change the particle type to 'Sprite'
- Under the texture layer, chose the Particle layer which you set as hidden earlier
With the settings changed, you should now have something that looks like this:
Now duplicate the same layer, and shift the Position XY to the right hand side. You can now see how you've created a smoke-like pattern.
Finally, precompose all of your layers and add a stroke from the layer styles. This will outline the entire smoke composition. Add an adjustment layer and apply the tint effect to it from your presets. You can now play around with the colours by remapping the black and white to the colours of your choice.
Finally, mask out and composite your smoke with your scene to add some magic to your illustrations.
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