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Fan - Unity

This section details the properties of the Fan object when the Modeler is using the Unity wind algorithm.

Note: Any property with a curve means it varies according to wind strength. The left side of the curve is the value when there is no wind and the right side is the value at maximum wind strength. Use these curves to control how the model transitions from a breeze to a storm.

Main

The properties in this group control wind quality and the enabled state.

Wind wizard...

Press the button to launch the Wind Wizard. This tool will set up the model based on your answers to a few questions about its components.

Preset

Controls the balance between performance and quality inside Unity. Options include:

No windThe model will be static in Unity. Fastest, lowest quality
FastestOnly global sway will be applied to the model.
FastGlobal sway and leaf ripple are applied to the model.
BetterGlobal sway, branch motion, and leaf ripple are applied to the model.
BestGlobal sway, branch motion, leaf ripple, and leaf tumbling are applied to the model.
PalmGlobal sway, branch motion, leaf ripple, leaf tumbling, and frond ripple are applied to the model. Slowest, best quality
Enabled

Use this property to toggle wind on and off in the Tree Window.

Settings

The properties in this group control high level wind settings.

Strength

This property sets the strength of the wind. 0.0 corresponds to no wind, 1.0 corresponds to the highest wind.

Note: The actual wind behavior is governed by how the properties below interpret the strength value. It is possible to have some wind at 0.0 and no wind at all at 1.0, depending on how the properties are tuned.

Response Times

These properties control how quickly the model responds to changes in wind strength and direction. Large, heavy models should have large response times. Small, light models should have short ones. For example, if a flower and an oak tree are placed under the influence of the same wind source, the flower should react more quickly to changes in that source than the oak tree does.

Strength

Sets the response time for strength changes. It is measured by how long, in seconds, it would take the model to go from 0.0 behavior to 1.0 behavior.

Direction

Sets the response time for direction changes. It is measured by how long, in seconds, it would take the model to react to a 180-degree change in wind direction.

Wind Anchor

The wind anchor is used only in conjunction with the “Palm” preset. The wind anchor is a point in space that moves around based on strength, direction, the shape of the tree, and the values of the properties in this group. Branches and fronds that use the wind anchor will bend toward this point when the wind blows. The wind anchor is indicated by a cyan dot near the tree.

Vertical offset

By default, the wind anchor will position itself at a height halfway up the model. Use this property to adjust its position up or down on the Z axis.

Distance Scale

The wind anchor will be positioned at a reasonable distance from the center of the model in the current wind directions. Use this property to scale that distance. Keep in mind that distances too far away from the model will lead to pronounced skewing during wind animation.

Scalars

The properties in this group scale the effect of several wind properties across all wind motion categories. Use these scalars to make sweeping changes to the entire animation (e.g., speed the whole thing up with a frequency scale).

Distance

Scales all wind motion distance properties (branch motion, leaf ripple, etc.).

Frequency

Scales all wind motion frequency values.

Direction adherence

Scales all direction adherence values.

Global Motion

Global Motion refers to the uniform swaying back and forth of the entire model.

Height exponent

Augments the swaying effect towards the top of the model. Increase this value to add some curvature to the swaying motion. The Skewing caused by this is somewhat (but not completely) corrected by the shader.

Distance

Controls how far, in world units, the model will sway in high wind conditions.

Frequency

Controls how fast the global motion oscillates. Most models will use a low number here and higher numbers for branch and leaf frequencies.

Direction adherence

Controls how much the model leans into the direction of the wind. Swaying occurs relative to this position.

Branch Motion

The properties in this group control the movement of the branches where “Wind:Apply” is checked (the first such branches from the Tree generator). These are the properties that control independent branch motion.

Distance

Controls how far branches will oscillate.

Frequency

Controls how rapidly branches will oscillate.

Whip

Enables this property to make branches appear more “rubbery”, as if a whip were being cracked in slow motion. The value controls how flexible the branch appears to be.

Direction adherence

Controls how much the branches lean into the direction of the wind. Swaying occurs relative to this position.

Turbulence

Controls how much chaotic motion is the branch direction adherence.

Sway bias

This property controls how likely a branch is to get “stuck” on one side of the oscillation before swinging over to the other.

Sway freq

This option controls how often “sways” from one side of the oscillation range to the other occur.

Note: The two “sway” properties in this group combine to make the oscillations more complex than a simple sine wave.

Leaf Motion

The properties in this group control the behavior of leaf meshes.

Note: Some of these properties may be hidden for performance reasons based on the “Preset” selection.

Ripple

Leaf rippling is the act of the leaf geometry vertices oscillating back and forth along their surface normal.

Distance

Controls how far the vertices will move during oscillation.

Frequency

Controls how fast leaf vertices will oscillate.

Tumble

Leaf tumbling is the act of individual leaf meshes rotating around their anchor point. This effect is significantly more expensive than rippling from a performance standpoint.

Flip

Controls how much the leaf rotates in the direction of the wind.

Twist

Controls how much the leaf rotates in a direction orthogonal to the wind.

Frequency

Controls how fast the leaves oscillate.

Direction adherence

Controls how much the leaves point in the direction of the wind (leaves are pointed before they oscillate).

Twitch

Leaf twitching simulates the periodic flips and twists of leaves separate from their nominal oscillations. Use these properties to make leaf motion more chaotic.

Throw

Controls how much more leaves “flip” when a twitch occurs.

Frequency

Controls how often twitches might happen.

Sharpness

Controls how quickly leaves get in and out of a twitch.

Frond Motion

Frond animation is achieved by oscillating frond vertices along their surface normal in a manner similar to leaf rippling. This motion is available only when using the “Palm” preset.

Distance

Controls how far the vertices will move during oscillation.

Frequency

Controls how fast frond vertices will oscillate.

Tile

Controls how much the ripple effect is tiled across the frond. Increase this value for a tighter pattern.

Adjust lighting

When enabled, frond ripple affects the geometry normals, resulting in slower performance but better lighting (particularly better specular effects).

Lighting scalar

When “Adjust lighting” is enabled, this value scales how much the normals are modified by frond rippling.

Gusting

The properties in this group control the timing and strength of random wind gusts.

Enabled

Toggles gusting on and off.

Frequency

Controls how often gusts can occur.

Strength

Controls how much additional wind strength is added to the nominal wind strength during a gust. Add variance to make each gust random.

Duration

When a gust happens, this value controls how long it will remain active (in seconds). Use the variance to make each gust length random.

Response Scalars

Rise

This value scales how long it takes for a gust to reach its maximum value. Lower this value to increase the speed at which gusts impact the model.

Fall

This value scales how long it takes for a gust to return to the nominal wind level. Lower this value to increase the speed at which the model returns to nominal wind conditions after a gust.