Adobe 12040118 - After Effects Standard, Руководство

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6. Click the Font Size value, type a value of 10 or greater, and press Enter (Windows) or Return (Mac OS).
If you want to stop replacing default particles with text, delete all text from the box in the Edit Grid Text dialog box.
Using Selection Text values to differently affect subsets of text
You can differently affect only certain subsets of text particles by specifying Selection Text values. To open the Particle Playground options dialog
box, click Options at the top of the Particle Playground entry in the Effect Controls panel. (This is the same place where you can specify the text
used by the Grid or Cannon emitters.) Then enter text in one or more of the Selection Text fields, and click OK. After doing this, you can then
choose one of the Selection Text sets from the Character menu under one of the Affects property groups. For example, you can make gravity only
affect the letter e by entering e in Selection Text 1 and then choosing Selection Text 1 in Gravity > Affects > Characters.
Note: The string matching is case-sensitive, and it does include punctuation marks and other symbols.
As with all text features, consider using this feature with symbol fonts, like wingdings.
Changing a particle over its lifespan
Some controls affect the particle from birth: Cannon, Grid, Layer Exploder, and Particle Exploder. Others affect the particle after birth and over the
course of its lifespan: Gravity, Repel, Wall, Persistent Property Mapper, and Ephemeral Property Mapper. To have full control over particle
movement and appearance, you must balance these controls.
For example, if you want to use the Cannon to shoot sparks that fade over time, it may seem that you need only animate the Color control of the
Cannon. However, using this method, you change only the color of each new particle as it’s created. To control the color for the lifespan of
particles, create a layer map and use one of the Property Mappers to alter the color channels of the particles.
The following list covers common particle behavior and how you can influence it.
Speed At particle creation, particle velocity is set by the Cannon and the exploders; Grid particles have no initial speed. After particle creation, use
the Force control in the Gravity and Repel control groups. You can also influence the speed of individual particles by using a layer map to set
values for the Speed, Kinetic Friction, Force, and Mass properties in the Property Mappers.
Direction At particle creation, the Cannon includes particle direction; the Layer Exploder and Particle Exploder send new particles in all directions;
and Grid particles have no initial direction. After particle creation, direction can be influenced by the Direction control in the Gravity control group or
by specifying a Boundary (mask) in the Wall control group. You can also influence the direction of individual particles by using a layer map to set
values for the Gradient Force, X Speed, and Y Speed properties in the Property Mappers.
Area Use a Wall mask to contain particles to a different area or to remove all barriers. You can also restrict particles to an area by using a layer
map to set values for the Gradient Force property in the Property Mappers.
Appearance At particle creation, the Cannon, Grid, Layer Exploder, and Particle Exploder set particle size unless you replace the default dots with
a layer map. The Cannon and Grid set the initial color, while the Layer Exploder and Particle Exploder take color from the exploded dot, layer, or
character. The Options dialog box affects the initial appearance of text. After particle creation, you can use the Property Mappers to set values for
Red, Green, Blue, Scale, Opacity, and Font Size.
Rotation At particle creation, the Cannon and Grid set no rotation; the Particle Exploder takes rotation from the exploded dot, layer, or character.
Use Auto-Orient Rotation to make particles rotate automatically along their respective trajectories. For example, a particle can point up as it climbs
an arc, and point down as it descends. Rotation isn’t easily visible for a dot particle. It is easier to observe only when you replace the dot particle
with text characters or a layer. After particle creation, use a layer map to set values for the Angle, Angular Velocity, and Torque property in the
Property Mappers.
Note: To select Auto-Orient Rotation, click Options for the Particle Playground effect in the Effect Controls panel.
Gravity controls
Use Gravity controls to pull existing particles in a direction you specify. Particles accelerate in the direction of gravity. Apply in a vertical direction to
create falling particles, such as rain or snow, or rising particles, such as champagne bubbles. Apply in a horizontal direction to simulate wind.
Force Specifies the force of gravity. Positive values increase the force, pulling particles more strongly. Negative values reduce the force.
Force Random Spread Specifies a range of randomness for the Force. At zero, all particles fall at the same rate. At a higher value, particles fall
at slightly different rates. Although pure gravity accelerates all objects equally, increasing the Force Random Spread value can produce more
realistic results with subjects such as leaves falling through air, where enough air resistance exists to vary the rates of descent of the leaves.
Direction Specifies the angle along which gravity pulls. The default is 180°, which simulates the real world by pulling particles toward the bottom
of the frame.
Affects Specifies a subset of the layer’s particles to which Gravity applies.
Repel controls
Repel controls specify how nearby particles repel or attract each other. This feature simulates adding a positive or negative magnetic charge to
each particle. You can specify which particles, layers, or characters are the repelling force and which are repelled.
Note: If you want to repel an entire layer of particles away from a specific area, use the Property Mapper controls, Wall or Gradient Force.
Force
Specifies the repel force. Greater values repel particles with more force. Negative values result in particle attraction.
Force Radius Specifies the radius (measured in pixels) within which particles are repelled. Another particle must be within this radius to be
repelled.
Repeller Specifies which particles act as the repellers or attractors to another subset you specify by using the Affects control.
Affects Specifies a subset of the layer’s particles to which repulsion or attraction applies.