Light and Chunky

Light and Chunky

Each explosion you will see is unique, but to narrow the
discussion, I’ll organize all explosions into two basic categories.
The easier one to deal with is the gaseous explosion—
one made up only of gas and heat. These explosions
behave just like fi re; in fact, in the shot in Figure 14.20a
the explosion is fi re, a huge ball of it, where something
very combustible evidently went up very quickly.
Some shots end up looking fake because they use a gaseous
explosion when some chunks of debris are needed. This
is a prime reason that exploding miniatures are still in
use, shot at high speed (or even, when possible, full-scale

explosions, which can be shot at standard speed). The
slower moving and bigger the amount of debris, the bigger
the apparent explosion.
If your shot calls for a chunky explosion, full of physical
debris, and the source lacks them, you need an alternate
source. Many 3D programs these days include effective
dynamics simulations; if you go that route, be sure to
generate a depth map as well because each chunk will be
revealed only as it emerges from the fi reball. Many other
concerns associated with this are beyond the scope of this
discussion because they must be solved in other software.
One effect that seems to come close in After Effects is Shatter,
but it’s hard to recommend this unless it is specifi cally
a pane of glass or other plane that breaks. Shatter isn’t bad
for a decade-old dynamics simulator, but its primary limitation
is a huge one: It can employ only extruded fl at polygons
to model the chunks. A pane of glass is one of the few
physical objects that would shatter into irregular but fl at
polygons, and Shatter contains built-in controls for specifying
the size of the shards in the point of impact. Shatter
was also developed prior to the introduction of 3D in After
Effects; you can place your imaginary window in perspective
space, but not with the help of a camera or 3D controls.
A wide selection of pyrotechnic explosions is also available
as stock footage from such companies as Artbeats. In many
cases, there is no substitute for footage of a real, physical
object being blown to bits.