Limit Modifier

With this modifier you can limit the movement of particles by preventing them from moving in one or more planes. So for example, if you have a Turbulence modifier in the scene, the Limit modifier could be used to restrict movement to the X and Z axes, with no movement along the Y axis.

Note that if you set the limit to 100% in all three fields, the particles will not move at all!

This modifier was originally written by Paul Taylor in Python using the X-Particles API. Paul generously allowed us to convert his modifier into a full inbuilt modifier for the particle system.

Interface

This is the modifier's interface:

For the 'Groups Affected', 'Mapping', and 'Falloff' tabs, and for the buttons at the bottom of the interface, please see the 'Common interface elements' page.

Parameters

Enabled

Uncheck this switch to disable the modifier.

Mode

Independent [default setting]

In this mode, the modifier will work in the same way as a standard Cinema 4D particle modifier: particles will be affected if they come into the field of effect of the modifier. X-Particle Actions have no effect on the modifier in this mode.

Action-Controlled

In this mode, the modifier will only act on a particle when told to do so by an Action. Until that point, the particle will not be affected, but once activated for a particular particle, the modifier will continue to influence it as long as it is in the field of effect of the modifier. The modifier's effect on a particle can be halted by means of another Action, if desired.

Use Emitter Space

If this space is unchecked, the axes on which movement is limited will be the global, 3D world, axes. If it is checked the emitter axis is used instead. You will only see a difference if the emitter is rotated so its axes are not aligned with the world axes. Note that this setting has no effect if you are emitting from an object, only if you emit directly from an emitter.

Axis Limit

This is the limit, in percentage terms, of movement on the three axes. A value of zero means no limit, a value of 100% results in no movement at all on that axis.

In X-Particles 4, the three components (X, Y, and Z axes) of the 'Axis Limit' parameter can now be mapped individually. Previously, the mapping was an overall effect which affected each axis equally.

X-Axis Restriction

This drop-down has three settings:

None

There is no restriction on the X-axis other than the value in 'Axis Limit' if that is greater than zero.

X+

X-axis movement is restricted to the positive axis. This can be combined with the 'Axis Limit' setting to reduce movement along the other axes.

X-

X-axis movement is restricted to the negative axis. This can be combined with the 'Axis Limit' setting to reduce movement along the other axes.

Y-Axis Restriction. Z-Axis Restriction

These operate in the same way as for the 'X-Axis Restriction'.

No Banking

When particles turn to move in a different direction, the bank component of their rotation is often changed automatically. This looks natural for such things as birds, but if you watch a school of fish, they do not appear to bank on turning.

If you would prefer that the particles emulate that behaviour and don't bank when turning, you can use this modifier with 'No Banking' checked.