These options appear in the Paint Effects Brush Settings window, and the Attribute Editor for any brush node.
Use the Flow Animation settings to animate tube growth, and the flow of gaps, twists, and textures along each tube.
For more information, see Animate tube growth, gaps, twist, and textures.
- Flow Speed
-
Defines the speed (in cycles per second) and direction that gaps, twists, and textures flow along animated tubes. Positive numbers make them flow from base to tip. Negative numbers make them grow and flow from tip to base.
For example, if the flow speed is two, the gap, twist, or texture pattern cycles (flows back to the starting pattern) twice in one second. So if your units are defined to be 24 frames per second, the pattern made by the gap, twist, or texture pattern will be identical on the 12th frame and the 24th frame.
If you turn on the Time Clip or Stroke Time options, it also defines the speed that tubes grow.
- Texture Flow
-
This moves the texture with flow as defined by Flow Speed. In general this is best turned off for growth animations (growth with time clipping) because the textures will not move during the plant growth. But this is useful when you want a texture, particularly a displacement, to flow down the tubes. This is on by default.
- Stroke Time
-
This option has no effect unless Time Clip is on. Turn on Stroke Time to animate tube growth and flow from the beginning of the growth simulation to the end of the growth simulation.
- Time Clip
-
Turn on Time Clip so that animated tubes first appear and begin to flow at the time set by Start Time (seconds), and die at the time set by End Time (seconds).
If Time Clip is on, but Stroke Time isn’t, tubes along the stroke path are already planted, which means the tube growth is uniform.
If Time Clip is off, the tubes display at the end of their lifespan along the stroke, the growth simulation having completed. In this case, only gap, twist, or texture flow are animated.
- Start Time
-
This option has no effect unless Time Clip is on. Start Time (seconds) defines the time when tubes first appear (or are “born”).
Note: Start Time (seconds) is measured in seconds. So if your Time unit is set to 24 fps, for example (select , then click the Settings category), and the Start Time (seconds) is 1, then tubes will first appear on frame 24.If you know what frame you want tubes to appear on, divide this frame number by the frames per second defined by your Time unit to determine what value to enter in the Start Time (seconds) box. For example, if you want your tubes to appear on frame 60 and your Time unit is set to NTSC (30 fps), divide 60 frames by 30 frames per second, for a Start Time (seconds) of 2 seconds.
You can perform this calculation by creating an expression in the field. Type an equals sign (=) followed by the calculation. In the previous example, you would type:
=60.0/30
Notice that the time must have a floating point decimal.
- End Time
-
This option has no effect unless Time Clip is on. End Time defines the time when tubes “die.” If you think of a tube as a particle emitter that emits tube segments, the End Time is the point in time when the emitted segments die, or disappear. If the growth simulation is not yet complete, segments will continue to be emitted after the End Time until they reach their lifespan.
If you are animating growth, set this value to occur at the same frame as your end frame or later. With growth, you typically do not want tubes to die before the animation is complete.
To create “bursting” effects, use values that occur at frames before the end frame.
Note: End Time is measured in seconds. So if your Time unit is set to 24 fps, for example (select , then click the Settings category), and the End Time is 4, then tubes start to die on frame 96.If you know what frame you want tubes to begin to die on, divide this frame number by the frames per second defined by your Time unit to determine what value to enter in the End Time box. For example, if you want your tubes to begin to die on frame 120 and your Time unit is set to NTSC (30 fps), divide 120 frames by 30 frames per second, for an End Time of 4 seconds.
You can perform this calculation by creating an expression in the field. Type an equals sign (=) followed by the calculation. In the previous example, you would type:
=120.0/30
Notice that the time must have a floating point decimal.
- Time
-
Use this option to keyframe time. For example, if you are animating the growth of a tree, you can make the tree remain a sapling for the first 100 frames of the animation, then have the tree grow from a sapling to a full grown tree in the next 100 frames.
To keyframe time
- Right-click in the Time box and select Break Connection.
- Set keys at the frames you want to control growth (go to the frame, right-click in the Time box and select Set Key).
- Open the Graph Editor () and edit the animation curve to set the desired values. For details, see Graph Editor Curves menu.