nxRotate

Overview Video

nxRotate rotates the particle stream around an axis.

Object tab

Visible in Editor

Enabled by default, the direction for the particles is shown by an arrow in the viewport.

nxRotate icon when Visible in Editor is enabled. The nxRotate icon visually represents the rotation force applied to particles simulated in the scene and will rotate, in the viewport, when the Rotate Speed value is changed during animations.

Icon Size

Accessed by clicking the drop-down arrow to the left of the Visible in Editor parameter.

Use the slider, or manually input a value to change the icon size.

Type

Set as Force, by default.

The alternative is Velocity.

Force

In this mode, the change in velocity caused by this modifier contributes to, but does not control, the final particle velocity.

The particles will rotate, spiralling outwards strongly.

Adding a modifier (such as nxWind or nxTurbulence) will also contribute to the final result.

This is the mode to use if you want to add some other kind of movement to the particle as well as rotation.

Animation demonstrating the Type setting of Force.

Velocity

Here, the modifier takes complete control of the particle movement and the movement is much more contained.

If you add another modifier, which also influences particle speed and direction (e.g. nxTurbulence), you may find that it has little or no effect on the particle.

Animation using the Type setting of Velocity.

Rotate Speed

The rotation speed to use, in degrees per second.

At negative values, the particles will rotate the opposite (clockwise) way.

Animation showing the Rotate Speed value starting at 20°, increasing to 200° and then decreasing to - 200°.

Speed Multiplier

The speed of rotation will be changed by multiplying it by this value.

Animation demonstrating that increasing the Speed Multiplier value will accelerate the rotation forces.

Attraction

Only available if Type is set to Force, this slider will increase or decrease the attraction force of the particles.

At higher levels, the attraction will keep the particles contained in a tighter spiral.

Animated Attraction value, increasing from 0 (zero) to 200%.

Angular Accel

This is a value which is added to the Rotate Speed each frame.

This has the effect of speeding up (or, since negative values are allowed, slowing down) the rotation over time.

Clicking the drop-down arrow next to this parameter will display additional settings.

Animation showing the Angular Acceleration value decreasing from 50° to -50°.

Clamp

Set at Neither, by default, this drop-down menu enables you to clamp the maximum and minimum rotation speeds.

The alternative settings are: Both, Min and Max.

Neither

Neither the maximum or minimum speeds are clamped.

Both

Both speeds are clamped.

In this animation, the Min Rotation Speed is set at 50 degrees and the Max Rotation Speed is at 100 degrees, showing particles accelerating between those two speeds.

Min

Only the minimum speed is clamped.

Here, with a negative Angular Acceleration setting of -35 degrees, particles are slowing down until they reach the Min Rotation speed value of 10 degrees.

Max

Only the maximum speed is clamped.

Animation showing the clamping of Max Rotation Speed from 300° to 30°.

Min Rotation Speed

The minimum rotation speed permitted when this is clamped.

Max Rotation Speed

The maximum rotation speed permitted when this is clamped.

Escape Velocity

As the particles rotate, they are forced out from the centre of the rotation axis, just as if they were being influenced by centrifugal force.

This will cause them to travel at an ever-increasing speed.

If the particle speed exceeds the value in the Escape Velocity setting, they will cease to be affected by the modifier and will fly off, with their current speed and direction.

The lower this value, the lower the speed the particles must reach to ‘escape’ the modifier.

Escape Velocity animated from 6cm to 1cm, resulting in a dissolving particle effect.

Groups Affected tab

Groups

To specify the group, drag and drop the desired Group object into this field.

This setting is useful if you want to ensure that the spawned particles are, or are not, affected by nxRotate.

Mapping tab

The modifier’s settings can be mapped to particle data.

Use the dedicated manual page, below, for instructions on how this works.

Mapping

Fields tab

You can use the Fields options to control where nxRotate operates.