Spatial Offsets
3D animators will be familiar with the idea that every
object (or layer) has a pivot point. In After Effects, there
are two fundamental ways to make a layer pivot around a
different location: change the layer’s own Anchor Point
setting, or parent it to another layer.
After Effects is generally designed to preserve the appearance
of the composition when you are merely setting up
animation, toggling 3D on, and so forth. Therefore editing
an anchor point position with the Pan Behind tool triggers
the inverse offset to the Position property. Parent a layer to
another layer and the child layer maintains its relative position
until you further animate either of them.
It’s typically best to set up your offsets and hierarchy before
animating, although this section shows how to go about
changing your mind once keyframes are in place. The
Option key is key to all options.
Anchor Point
The Pan Behind tool (Y) repositions an anchor point in
the Composition panel and offsets the Position value to
compensate. This prevents the layer from appearing in a
different location on the frame in which you’re working.
The Position offset is for that frame only, however, so if
there are Position keyframes, the layer may appear offset
on other frames if you drag the anchor point this way. To
reposition the anchor point without changing Position
. Change the Anchor Point value in the Timeline
. Use the Pan Behind tool in Layer view instead
. Hold the Option key as you drag with the Pan Behind
tool
Any of these options lets you reposition the anchor point
without messing up an animation by changing one of the
Position keyframes.
You can also animate the anchor point, of course; this
allows you to rotate as you pan around an image while
keeping the view centered. If you’re having trouble seeing
the anchor point path as you work, open Layer view and
choose Anchor Point Path in the View pop-up menu
Parent Hierarchy
Layer parenting, in which all of the Transform settings
(except Opacity, which isn’t really a Transform setting) are
passed from parent to child, can be set up by revealing the
Parent column in the Timeline. There, you can choose a
layer’s parent either by selecting it from the list, or by dragging
the Pickwhip to the parent layer, and use the setup as
follows:
. Parenting remains valid even if the parent layer moves,
is duplicated, or changes its name.
. A parent and all of its children can be selected by
context-clicking the parent layer and choosing Select
Children.
. Parenting can be removed by choosing None from the
Parent menu.
. Null Objects (Ctrl+Alt/Command+Option+Shift+Y)
exist only to be parents; they are actually 100 × 100
pixel layers that do not render.
You probably knew all of that. You might not know what
happens when you add the Option key to Parent settings:
. Hold Option as you select the None option and the
layer reverts to the Transform values it had before
being parented (otherwise the offset at the time None
is selected remains).
. Hold Option as you select a Parent layer and its Transform
data at the current frame applied to the child
layer prior to parenting.
This last point is a very cool and easily missed method for
arraying layers automatically. You duplicate, offset, and
parent to create the fi rst layer in a pattern, then duplicate
that layer and Option+Parent it to the previous duplicate.
It behaves like the Duplicate and Offset option in Illustrator
Motion Blur
Motion blur is obviously essential to a realistic shot with a
good amount of motion. It is the natural result of movement
that occurs while a camera shutter is open, causing
objects in the image to be recorded at every point from the
shutter opening to closing. The movement can be individual
objects or the camera itself.
Although it essentially smears layers in a composition,
motion blur is generally desirable; it adds to persistence
of vision, relaxes the eye, and is a natural phenomenon.
Aesthetically, it can be quite beautiful.
The typical idea with motion blur in a realistic visual effects
shot is to match the amount of blur in the source shot,
assuming you have reference; if you lack visual reference, a
camera report can also help you set this correctly.
A moving picture camera has a shutter speed setting that
controls the amount of motion blur. This is not the camera’s
frame rate, although the shutter does obviously have
to be fast enough to accommodate the frame rate. A typical
fi lm camera shooting 24 frames per second has a shutter
that is open half the time, or 1⁄48 of a second.
Motion blur occurs in your natural vision, although you
might not realize it—stare at a ceiling fan in motion, and
then try following an individual blade around instead and
you will notice a dramatic difference. There is a trend in
recent years to use extremely high-speed electronic shutters,
which drastically reduces motion blur and gives the
psychological effect of heightened awareness by making
your eye feel as if it’s tracking motion in this manner.
This seems to have started with live television sports coverage
and the use of extremely fast shutters for slow motion
replay cameras.
3D animators will be familiar with the idea that every
object (or layer) has a pivot point. In After Effects, there
are two fundamental ways to make a layer pivot around a
different location: change the layer’s own Anchor Point
setting, or parent it to another layer.
After Effects is generally designed to preserve the appearance
of the composition when you are merely setting up
animation, toggling 3D on, and so forth. Therefore editing
an anchor point position with the Pan Behind tool triggers
the inverse offset to the Position property. Parent a layer to
another layer and the child layer maintains its relative position
until you further animate either of them.
It’s typically best to set up your offsets and hierarchy before
animating, although this section shows how to go about
changing your mind once keyframes are in place. The
Option key is key to all options.
Anchor Point
The Pan Behind tool (Y) repositions an anchor point in
the Composition panel and offsets the Position value to
compensate. This prevents the layer from appearing in a
different location on the frame in which you’re working.
The Position offset is for that frame only, however, so if
there are Position keyframes, the layer may appear offset
on other frames if you drag the anchor point this way. To
reposition the anchor point without changing Position
. Change the Anchor Point value in the Timeline
. Use the Pan Behind tool in Layer view instead
. Hold the Option key as you drag with the Pan Behind
tool
Any of these options lets you reposition the anchor point
without messing up an animation by changing one of the
Position keyframes.
You can also animate the anchor point, of course; this
allows you to rotate as you pan around an image while
keeping the view centered. If you’re having trouble seeing
the anchor point path as you work, open Layer view and
choose Anchor Point Path in the View pop-up menu
Parent Hierarchy
Layer parenting, in which all of the Transform settings
(except Opacity, which isn’t really a Transform setting) are
passed from parent to child, can be set up by revealing the
Parent column in the Timeline. There, you can choose a
layer’s parent either by selecting it from the list, or by dragging
the Pickwhip to the parent layer, and use the setup as
follows:
. Parenting remains valid even if the parent layer moves,
is duplicated, or changes its name.
. A parent and all of its children can be selected by
context-clicking the parent layer and choosing Select
Children.
. Parenting can be removed by choosing None from the
Parent menu.
. Null Objects (Ctrl+Alt/Command+Option+Shift+Y)
exist only to be parents; they are actually 100 × 100
pixel layers that do not render.
You probably knew all of that. You might not know what
happens when you add the Option key to Parent settings:
. Hold Option as you select the None option and the
layer reverts to the Transform values it had before
being parented (otherwise the offset at the time None
is selected remains).
. Hold Option as you select a Parent layer and its Transform
data at the current frame applied to the child
layer prior to parenting.
This last point is a very cool and easily missed method for
arraying layers automatically. You duplicate, offset, and
parent to create the fi rst layer in a pattern, then duplicate
that layer and Option+Parent it to the previous duplicate.
It behaves like the Duplicate and Offset option in Illustrator
Motion Blur
Motion blur is obviously essential to a realistic shot with a
good amount of motion. It is the natural result of movement
that occurs while a camera shutter is open, causing
objects in the image to be recorded at every point from the
shutter opening to closing. The movement can be individual
objects or the camera itself.
Although it essentially smears layers in a composition,
motion blur is generally desirable; it adds to persistence
of vision, relaxes the eye, and is a natural phenomenon.
Aesthetically, it can be quite beautiful.
The typical idea with motion blur in a realistic visual effects
shot is to match the amount of blur in the source shot,
assuming you have reference; if you lack visual reference, a
camera report can also help you set this correctly.
A moving picture camera has a shutter speed setting that
controls the amount of motion blur. This is not the camera’s
frame rate, although the shutter does obviously have
to be fast enough to accommodate the frame rate. A typical
fi lm camera shooting 24 frames per second has a shutter
that is open half the time, or 1⁄48 of a second.
Motion blur occurs in your natural vision, although you
might not realize it—stare at a ceiling fan in motion, and
then try following an individual blade around instead and
you will notice a dramatic difference. There is a trend in
recent years to use extremely high-speed electronic shutters,
which drastically reduces motion blur and gives the
psychological effect of heightened awareness by making
your eye feel as if it’s tracking motion in this manner.
This seems to have started with live television sports coverage
and the use of extremely fast shutters for slow motion
replay cameras.
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