EFFECTS |
Flock Animation |
The Effects->Flock Animation command in the Motion module allows you to animate flocks of a particle model to achieve a variety of effects, such as fireworks, snowstorms, fuses, or sprinklers. Three user-defined mesh objects are used: a source polygon mesh, a destination polygon mesh, and a particle model.
By default, flock animation is a shape animation and the particle must be a polygon mesh. You can, however, animate your flock by transformations. This allows you to use a meta-clay element or patch-based model as your particle.
You are prompted to pick the source polygon mesh, the destination polygon mesh, and the particle model in this order. Now play back your flock animation and view the results.
Note:
You can cancel the flock animation after selecting the source polygon mesh or the particle model by right-clicking.
Name
Name of the flock animation file if you want to save this effect. Flock animation files are saved with an .flk extension.
Number of Particles
The number of the particle models ("birds" in the flock) to participate in the flock animation.
Number of Key Shapes
The number of key shapes used to move the particles from the source mesh to the destination mesh. Keep the number as low as possible to save memory and computation time. However, if you have assigned attributes, such as gravity or set particle tracking of an animated destination to the flock animation, increase the number of key shapes (4 or 5 is sufficient for a typical arc).
Note:
If the Animate by Transforms option is selected, the number of key shapes is the number of keys.Source Vertices
When this option is selected, a particle mesh is placed at each vertex of the source mesh, so that the number of particles in the flock is equal to the number of vertices on the source polygon mesh.
Destination Vertices
When this option is selected, the particles participating in the flock animation land on the vertices of the destination polygon mesh.
Note:
If both Source and Destination Vertices option are selected and there are a different number of vertices in each polygon mesh, the particles leave from the source's vertices and land at random points on the destination object.Source Seed
Source seed numbers are used to create a specific random particle distribution pattern at the source mesh; that is, different source seed numbers yield different particle distribution patterns.
This parameter is useful if you want to have several flock animation particle models leaving from the same source polygon mesh. By assigning the same or a different source seed number, you can ensure that the particle distribution pattern for each flock animation is the same or different.
Destination Seed
Refer to Source Seed.
If the source and destination seed numbers are the same, and the source and destination polygon meshes are geometrically identical (such as if the destination mesh was created by duplicating and moving the source mesh), the particles travel from the source polygon mesh to the corresponding points on the destination polygon mesh. If this is not the desired effect, specify different source and destination seed numbers.
Start Frame
The starting frame number for the beginning of the flock animation.
Stop Frame
The ending frame number for the flock animation to finish.
Note:
The number of frames from start to end is the flight time for the specified particle.Gravity
The relative magnitude of the gravitational force applied to the particles. The greater the gravity, the steeper the arc.
Up Vector
Defines the direction of the gravitational force. For example, if the Up Vector is set to 0, 1, 0, gravity pulls the particles down in the
y-axis direction.Repetitions
The number of copies of the defined flock travelling from the source to the destination mesh in a single flock animation.
This option is useful for creating effects that require several flocks to leave the source polygon mesh in sequence, such as a spray of water. You can control how the flocks are sequenced using the Frame Offset, Frames to Hide, and Seed Offset parameters.
Note:
When calculating the cost in terms of memory, remember that the total number of particles used in the final animation is the number of particles in a flock multiplied by the number of repetitions.Frame Offset
The number of frames separating each repetition.
Seed Offset
The seed number is incremented by the amount you specify for each repetition.
Note:
If the Seed Offset value is 0, each repetition has the same seed value. This yields a more regular or repetitive looking motion.Frames to Hide
The number of frames to hide after a flock reaches the destination mesh.
Note:
If the Frames to Hide value is greater than zero, and the flock animation contains a single flock, the particle models disappear when they land at the destination.Jittering
Jitters each particle in a flock during flight to create subtle distinctions between them.
Jittering is applied randomly at each computed shape frame. You can apply scale, rotation, translation, or shape jittering to the x, y and
z-axes.Scale
A value of 0.5 means the scale factor is between 1 and 1.5.
Rotate
A value of 0.5 means the rotation is between 0 and 180 degrees.
Trans
A value of 0.5 means the offset is between 0 and 0.5 units.
Shape
A value of 0.5 means each vertex is offset between 0 and 0.5 units.
Hide before Start
Hides the particles before they leave the source polygon mesh.
Cyclic Extrapolation
When this option is selected, the flock animation cycles.
Note:
To create a realistic cyclical animation, set the Repetitions and Frame Offset parameters so that the animation is filled out. To do this, use the following equation:
(Stop Frame - Start Frame + 1) = (Repetitions x Frame Offset)Sample by Area
Distributes particles proportionally to the polygon area on both source and destination meshes by polygon.
Track Destination
When this option is selected, the particles track a moving destination mesh. When the BackTrack option is selected, subsequent repetitions leaving the source polygon mesh at different frames backtrack to the original motion of the destination.
Interpolate Materials
When this option is selected, a predefined material animation on the particle mesh in your flock animation. When using this option, verify that the Start and Stop Frame numbers correspond to the frame numbers set for the material animation on the particle mesh.
When the BackTrack option is selected, subsequent repetitions backtrack to the original material. If the option is not selected, the particles inherit the material animation present on the particle model at the frames used during the repetition's cycle.
Note:
The materials are keyed to the shape keys for flock animation. To view a complicated material animation with several keyframes, it may be necessary to increase the number of key shapes to view the full material animation.Animate by Transforms
Uses keyframe transformations to animate each member of the flock. This option is deselected by default.
Fixed Orientation
The x-axis of the particle model is fixed to the up vector.
SAVE
Saves the current Flock Animation parameters to a file using the name you specified in the Name text box. A file browser appears and prompts you to specify a name if you didn't supply one. Flock animation files are saved with an .flk extension.
BROWSER
Allows you to retrieve a previously saved flock animation file.
Last updated 02-apr-1998