Tricks and Gotchas

Tricks and Gotchas

Suppose the clone source time is offset, or comes from
a different layer, and the last frame of the layer has been
reached—what happens? After Effects helpfully loops back
to the fi rst frame of the clip and keeps going. This is dangerous
only if you’re not aware of it.
Edit the source to take control of this process. Time remapping
is one potential way to solve these problems; you can
time stretch a source clip or loop it intentionally.
You may need to scale the source to match the target.
Although temporal edits, including time remapping,
render before they are passed through, other types of

edits—even simple translations or effects—do not. As
always, the solution is to precompose; any scaling, rotation,
motion tracking, or effects to be cloned belong in the
subcomposition.
Finally, Paint is an effect. Apply your fi rst stroke and you’ll
see an effect called Paint with a single checkbox, Paint
on Transparent, which effectively solos the paint strokes.
You can change the render order of paint strokes relative
to other effects. For example, you can touch up a greenscreen
plate, apply a keyer, and then touch up the resulting
alpha channel, all on one layer.
The View menu in the Layer panel  lists, in
order, the paint and effects edits you’ve added to the layer.
To see only the layer with no edits applied, toggle Render
off; to see a particular stage of the edit—after the fi rst
paint strokes, but before the effects, say—select it in the
View menu, effectively disabling the steps below it. These
settings are for previewing only; they will not enable or disable
the rendering of these items.You can motion track a paint stroke.
To do so requires the tracker, covered in the next chapter, and a basic
expression.