Trapcode Particular
Displace -Turbulence Field
The Displace group offers two kinds of displacement models to push along the particles. One is Turbulence Field, based on a 3D displacement of a Perlin Noise fractal. Turbulence adds motion so particles that are close to each other get a similar, but not equal, random motion.
This behavior helps tremendously when creating fire and smoke effects to make particle motion look natural. Turbulence computes fast and can be freely scrubbed back and forth in the Timeline. It should be noted that Air Turbulence is available in the Environment section and may be more suitable for certain animations however those turbulence properties are not compatible with Fluid Physics simulations or the Classic Form behavior. The Displace Turbulence Field is.
If you want to know about the inner workings of Turbulence Field, go to the end of this page to read about Perlin Fractal Noise.
TF Affect Size
TF Affect Size enables using the fractal for particle size distortion. Setting up this parameter means the fractal field will be sampled at each particle's location, and the size of that particle will be affected by the value of the field. This can be useful for creating cloud-like particle clusters.
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Affect Size Off
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Affect Size On |
TF Affect Opacity
TF Affect Size enables using the fractal for particle size distortion. Setting up this parameter means the fractal field will be sampled at each particle's location, and the size of that particle will be affected by the value of the field. This can be useful for creating cloud-like particle clusters.
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Affect Opacity Off |
Affect Opacity On |
TF Displacement Mode
Allows you adjust the displacement uniformly, individually along the X,Y and Z axis or radially.
Fractal Strength Over Pop-Up
Sets the axis for the Fractal Strength Curve. This determines how the displacement affects the form. Note: This is only available with Form behaviors. See the Using Curves page for more information.
Fractal Strength Curve
Allows you to control the strength of the displacement of the particles across the form. This is available when Fractal Strength Over is set to anything but off. See the Using Curves page for more information.
Fractal Strength Curve Offset
Universally adjusts all values of the Fractal Strength Curve and allows you to animate the values of the curve. This is available when Fractal Strength Over is set to anything but off. See the Using Curves page for more info about curves.
Fade-in Time (seconds)
Fade-in Time sets the amount of time in seconds before the particles are fully affected by the Turbulence Field. High values means the Turbulence takes a while to affect the particles, which makes the animation fade in gradually over time.
Fade-in Curve
This is a fade-in curve control for Turbulence Field. Smooth is on by default, and fades in the field more subtly. Linear gives a linear interpolation to the curve, which can sometimes produces a jerk in the animation.
Turbulence Field Controls
A group that gives you control over the underlying fractal driving the Turbulence Field offsets.
- TF Scale : sets the overall scale of the fractal.
- TF Complexity : the number of Perlin noise fields added together to form the fractal.
- TF Octave Multiplier : sets the influence of each added noise field as compared to the previous field.
- TF Octave Scale : sets the scale of each added noise field compared to the previous.
- TF Evolution Speed : sets how fast the Turbulence Field evolves over time.
- TF Evolution Offset : offsets the Turbulence Field in time. Evolution Offset gives more control over how the Turbulence Field can be moved.
- TF Offset X, Y, Z : these three controls offset the entire Turbulence Field in each axis. This also gives more control over how the Turbulence Field can be moved.
- Flow X, Flow Y, Flow Z: Controls the speed of motion in each direction as the fractal field is moved through the particle grid.
- Flow Loop: When this checkbox is turned on, the fractal field will loop after a specified time. That time is specified in Loop Time. This is turned off by default, which makes a seamless loop that can be repeated endlessly. When this checkbox is turned on, Particular will perform some internal tests and report if a seamless loop is not possible with the current settings. If the loop isn't possible, try increasing the Loop Time and/or the FlowX,Y or Z values
- Loop Time [sec]: Defines the time in seconds before the fractal loop repeats. This is turned on when the Flow Loop checkbox is enabled. For example, if Loop Time is set to 4seconds, then the first frame and frame 4:00 will have identical fractal fields. This in turn means that frame 5:00 is NOT part of the loop. So if you are using this as a looping background, be sure to remove the last frame of the loop, and the playback will seamlessly loop over the specified time interval.
TF Move with Wind
TF Move with Wind gives the ability to move the Turbulence Field with the Wind X, Y, Z controls in Environment. Measured as a percentage of the Wind value. At 100%, the Turbulence Field follows the Wind exactly. At 50%, it still follows the Wind's direction, but only 50% of the distance.
This control gives a very realistic look to fire and smoke effects. It is useful for getting a natural look in making wind, since the Turbulence Field moves with the wind as it would in real life.
TF Move with Drift
TF Move with Drift gives the ability to move the Turbulence Field with the Drift X, Y, Z controls in Fast Physics. Measured as a percentage of the Drift value. At 100%, the Turbulence Field follows the Drift exactly. At 50%, it still follows the Drift's direction, but only 50% of the distance.
How it works: Perlin Noise Fractal Theory
In order to fully comprehend the Turbulence functionality, some Perlin Noise fractal theory helps. Perlin Noise was invented by Ken Perlin. (Kudos to Mr. Perlin, this is amazing stuff!) Perlin Noise is a quick way to produce a pseudo-random field that can be of any dimensionality (1D, 2D, 3D, etc).
The field is 'smooth' and can look something like this (2D):
If the same field is scaled down or 'zoomed out', it looks something like this:
Now, if a couple of these fields with different scales are added together, they form what is called a Perlin Noise Fractal:
The number of fields added together is called Complexity . For example, if three fields are added together, complexity equals three. The difference in scale for each field is called Octave Scale and the difference in influence for each field is called Octave Multiplier . The images above were created using Adobe After Effects' built-in Perlin Noise fractal generator (Effect>Noise>Fractal Noise). The really interesting part of Perlin Noise is that these fractals can be evolved over time. What is seen in the images above is actually a cross section of a 3D Perlin Noise fractal. The cross section can slide through 3D space and thus create a smoothly evolving 2D pattern. This parameter is called Evolution . In Trapcode Particular, a 3D displacement field is needed. This requires the Perlin Noise fractal to be 4D so it can smoothly evolve by sliding the 3D cross-section in time. And now you've been initiated into Fractal Noise Theory!