Fog, Smoke, and Mist

Fog, Smoke, and Mist

An animated layer of translucent clouds is easy to re-create
in After Effects. The basic element can be fabricated by
applying the Turbulent Noise effect to a solid, then adding
a blending mode such as Add or Screen with the appropriate
Opacity setting. On the book’s disc, 13_smokyFlyover.
aep contains a simple example of layers of smoke laid out
as if on a three-dimensional plane.

Turbulent Noise at its default settings already looks smoky
; switching the Noise Type setting from the
default, Soft Linear, to Spline improves it. The main thing
to add is motion, which I like to do with a simple expression
applied to the Evolution property: time*60 (I fi nd
60 an appropriate rate in many situations, your taste may
vary). The Transform properties within Fractal Noise can
be animated, causing the overall layer to move as if being
blown by wind.
Brightness, Contrast, and Scale settings infl uence the
apparent scale and density of the noise layer. Complexity
and Sub settings also affect apparent scale and density,
but with all kinds of undesirable side effects that make the
smoke look artifi cial. The look is greatly improved by layering
at least two separate passes via a blending mode (as in
the example project).