Emission tab

This tab is concerned with particle emission and death.

Emission tab

Subframe Emit

Since particles are emitted each frame, regular 'bands' of particles may be generated.

This is especially noticeable when the emitter itself is animated.

Sub-frame emission helps to overcome this.

Normally you should leave this enabled but, if you need to turn it off, uncheck this box.

No Control System

If this is enabled, the X-Particles control system will be ignored by the emitter.

No Question objects will be tested and no actions carried out.

Emission

Set as Rate, by default, there are six more options: Pulse, Shot, Regular, Hexagonal, Trigger, Controlled Only.

Rate

This is the default setting; particles are emitted each frame at a rate determined by the Birthrate settings.

Animation to demonstrate the Emission setting as Rate.

Pulse

Normally, the emitter emits particles in all frames.

If you want the emitter to emit one big pulse of particles in one frame, turn on this option.

The number of particles emitted in each pulse is found in the Birthrate parameter.

Animation demonstrating Emission set as Pulse.

Note: With a high number of subframes, the number of particles emitted may be slightly higher than expected.

This is due to arithmetical rounding in the calculation of the number of particles to be emitted.

The pulse setting offers four additional parameter options.

This animation shows the effect of manipulating the Pulse Spline setting in the Emission mode of Pulse.

Length

You can specify the number of frames the pulse will last for here.

Interval

Set the number of frames between pulses here.

If you want just one pulse to be emitted in the scene, simply set this value to a higher number than the scene length.

Override Subframes

This parameter is intended for use when you have a pulse emitter which emits very small numbers of particles each pulse and the X-Particles subframe count is greater than 1.

Enabling this will cause the emitter to ignore the increased subframes when emitting in pulse mode and emit them only on the first subframe.

It is recommended that you leave this unchecked unless you are using multiple subframes in pulse mode and don't see the correct number of particles.

Pulse Spline

If you have a pulse with a Length value of greater than 1 frame you can control the emission over the pulse with this spline.

The spline gives best result with medium or large numbers of particles and a pulse length of 5 frames or more (any less and you won't see much effect).

Shot

In this mode, the emitter fires a single shot of particles on one or more frames.

Five additional parameters become available in this mode.

This animation demonstrates the Emission mode of Shot.

Shot Type

Set at Random, by default, particle emission positions are generated randomly.

The alternatives are Regular and Hexagonal, which are the same as the emission modes, described below.

Shot Time

The time when the shot will take place.

This can be animated to fire multiple shots.

Duration

The length of time for the shot.

Shot Count

The number of particles in the shot.

Per Frame

If this box is checked, on each frame the number of particles emitted is the value in Shot Count.

If it is unchecked, the value in Shot Count is a value per second.

Note: If the shot count is less than the number of frames specified in the Duration setting, no particles are emitted.

Regular and Hexagonal

These are special emission modes specifically for use with fluid simulations.

Although you can use them with standard emitters, such as the Rectangle or Circle settings, they are principally intended for use when emitting from an object.

If you select one of these modes, you will see that particles are only emitted from the object's volume and they are packed into the volume so as to ensure no overlapping particles.

This is because particles which overlap at birth can result in unstable or exploding fluid sims.

The difference between them is the method of packing.

Regular uses a regular grid (as in the MoGraph cloner) but Hexagonal uses a more efficient packing method allowing more particles to be emitted from the same volume.

Three additional parameters become available in this mode.

Jitter XY and Jitter Z

These settings allow you to disturb the regularity of the grid by offsetting the particle position across the plane of the emitter (Jitter XY) or along the particle direction (Jitter Z).

There will still be no overlap, so using these options will result in fewer particles being emitted.

Spacing

This setting enables additional space to be added between each particle.

If you make this too large, you may find that few or no particles are emitted.

Trigger

This mode allows you to fire a burst of particles at any desired time, rather than using continuous or pulsed emission.

Particles will only be emitted when Pull Trigger is enabled.

You can do this by keyframing the Pull Trigger tick box, turning the emitter on and off at set frames.

Alternatively, you can use Xpresso to set and unset the parameter.

The input to the Pull Trigger setting is a Boolean, so you can use any expression which evaluates to a Boolean to make particle emission start and stop.

Otherwise, you can use the Change Emitter action to pull or release the trigger (the Trigger Count option must be set to Set by Action for this to work, if it is not then no particles will be emitted).

Three additional parameters become available in this mode.

Trigger Count

The number of particles emitted in trigger mode uses the Birthrate setting by default.

You can change the Trigger Count drop-down to alter this.

Either use the Birthrate setting to determine the number of particles to emit, specify the number of particles in the Count field or set the number by the Change Emitter action.

Count

The number of particles to emit if Trigger Count is set to Specify.

Pull Trigger

Check this box to fire a burst of particles.

This is only useful when turned on and off by one of the methods described above.

Controlled Only

If this option is selected, the emitter will not emit any particles until told to do so.

This option will be set automatically by any other object which requires an emitter to generate spawned particle, for example a Spawn modifier, Collider tag, Particle-Particle Collisions object, etc.

It can also be used when the emitter Initial State is used or when an emitter is partially cached.

In both cases, you can set the emitter to this mode and it will only emit those particles stored in the initial state or by the cache and no more.

Important: This option is automatically selected when you drag an emitter into the link field of any X-Particles object which has a link for a spawning emitter, to prevent self-spawning.

A number of emitter settings are unavailable in this mode because they are not relevant when an emitter only spawns.

These are: Emit all Frames, Start Emit/End Emit, Birthrate and Variation.

Note: The emitter icon in the object manager changes when this mode is selected.

In addition, the color of the icon can be changed by using the Icon Color parameter in the Display tab.

Mode

Set as Simulate (Legacy), by default, this setting adds some important new options to how particles are emitted.

The other options are: Simulate and Motion.

Simulate (Legacy)

This is the conventional emission mode in which particles are first emitted on the first frame and not the base frame, which is usually frame 0 (zero) of the animation.

This is the default setting for backwards compatibility.

Simulate

This is identical to Simulate (Legacy) except that particles are emitted on the base frame.

This makes it possible to use the emitter as an advanced cloner-type object.

If you combine this with setting emission to Shot, then you will have a single shot of particles available on the base frame even before the animation plays.

Motion

In this mode the particles are emitted on the base frame, usually frame 0 (zero), but each subsequent frame the existing particles are destroyed and re-emitted.

For this reason they appear not to move, but they do have velocity - it's simply that they only live for one frame then are re-emitted in the same position (unless something else changes).

Emit all Frames

When this is set (it is on by default) the emitter will continue to emit particles from the start of the animation until the end (or until the maximum number of particles is reached).

If you disable this, you can then set when the emission starts and when it ends using the Start Emit and End Emit fields.

In this animation, Emit all Frames is enabled on the top and disabled on the bottom.

Start Emit, End Emit

These settings determine when particle emission starts and stops once you have disabled the Emit all Frames options.

Full Lifespan

This simply sets the lifespan of the particles to the length of the document.

When this is selected the Lifespan parameter is unavailable.

In this animation, Full Lifespan is enabled on the left and disabled on the right, both with a Birthrate setting of 500 particles.

Lifespan and Variation

The life of the particle in time units.

Once the particle’s life exceeds this value, it is removed from the scene.

This option is not available if Full Lifespan is checked.

You can add some variation to the particles' Lifespan with the Variation setting.

Birthrate and Variation

The number of particles emitted per second (not per frame), or per pulse if Pulse Emission is turned on.

You can add some variation to this number with the Variation setting.

Click the drop-down arrow to the left of the parameter to show three additional Birthrate parameter settings.

In this animation, Birthrate is set at 50 on the top and 500 on the bottom.

Birthrate Timing

Set at Per Second, by default, this setting controls how the Birthrate value is calculated.

Per Second

This means that the Birthrate value is the number of particles per second.

Per Frame

With this option, the Birthrate value is the number of particles per frame.

Birthrate Spline

You can use the Birthrate Spline to vary the birthrate over time.

The value in the spline is used to multiply the Birthrate value.

When a point is set at 1, the actual birthrate is the same as the value in the Birthrate parameter.

Values smaller than 1 will reduce the birthrate in proportion.

Animation demonstrating the effect of manipulating the Birthrate Spline, with contrasting settings on the left and right.

Shader

The birthrate can also be driven by a shader.

Add any shader to this link to see this.

Animated shaders can be used to produce varying birthrates.

In this animation, the contrasting emission pattern is being driven by the introduction of a Noise shader, on the bottom.

Sample Point

Set at Constant, by default, if a shader is added to the Shader link.

This setting controls how the shader is sampled to produce a value which is then used to calculate the number of particles to be emitted.

The alternative option is Random.

Constant

With this option the shader is always sampled in the same place.

This is the best option for use with animated shaders since the result of the sampling will be determined by the animation of the shader.

For non-animated shaders this option will always give the same result.

Random

Here, the shader will be sampled at a different, randomly-selected position each time.

This is the best option for non-animated shaders or bitmaps since the sample value will depend solely on the shader or bitmap at the sample position.

No Intersection

If enabled, the emitter will try to prevent particles intersecting at birth.

No Intersection disabled on the left, then enabled for the other two, with the Radius setting of 2cm, then raised to 4cm, separating the particles..

Radius

The Radius value is the size of the virtual sphere around the particle to check for intersections.

Basic Particle Data

This section lets you set the basic particle data that all particles have.

Speed and Variation

The particle’s initial speed in screen units per second and the option to add variation to this setting.

In this first animation the Speed values differ, with 150cm on the top and 50cm on the bottom.

The Speed values are both set at 150cm in this second animation. Variation is 0 (zero) cm on the top and 150cm on the bottom.

Radius and Variation

This is used for collisions and also determines the size of the particles in the editor when Spheres, Circle or Box are selected as the particle shape.

The particle Radius setting is 2cm on the top and 5cm on the bottom, in this animation.

In this final animation, the Radius setting is 3cm for both emitters. Variation is 0 (zero) cm on the top and 2.5cm on the bottom, allowing particles to be anywhere between 0.5 and 5.5cm in radius.

Scale and Scale Var

The particle scale.

This is used by the xpGenerator, xpSprite and xpFragmenter objects to scale the generated geometry.

Uniform Scale and Uniform Variation

If these boxes are checked, the value in each of the Scale and/or Scale Var fields are changed uniformly; a change in one vector component is made in the other two components.

This is a convenience feature to save having to change all three components to match.

If you need to set the components to different values, uncheck either or both boxes.

Particle Death

It is possible for actions to be triggered when a particle dies.

Drag the Action object(s) into the Actions list, or click the Add Action button to add an action.

For more information on Action objects, see the independent manual.

Actions

Drag and drop any actions to be carried out on particle death into this list box.

Add Action

Click this button to add an Action object to the scene and automatically add it to the list.

Motion Inheritance tab

If the emitter or the emission object moves or rotates, particles can inherit their speed and direction from them.

These settings will have no effect if the emitter or emission object are completely static.

In this animation, with the xpEmitter in motion, the effect of enabling the Use Motion Inheritance parameter is demonstrated.

Use Motion Inheritance

Check this box to enable motion inheritance.

Linear Direction

If enabled, this will cause the particles to inherit speed and direction from any linear motion of the emitter.

Rotational Direction

If enabled, this will cause the particles to inherit speed and direction from any rotational motion of the emitter.

Speed Blend

A value of 100% in this field will add the full contribution of the emitter's motion to that of the particles.

If set to 0 (zero) %, it would be the same as if motion inheritance was not used.

Thinking Particles tab

X-Particles can generate Thinking Particles in addition to its own particles.

This is essential if you want to render your particles with Pyrocluster or the Hair renderer, or you want to use particles with the Proximal shader.

It is also required for use with some other plugins which specifically require Thinking Particles.

When you generate Thinking Particles, X-Particles is still generating its own particles, but it generates Thinking Particles as well.

The xpEmitter above is generating regular particles. With Generate Thinking Particles enabled, the xpEmitter_TP below, is generating Thinking Particles.

Generate Thinking Particles

Check this box, to enable the generation of Thinking Particles.

This will automatically turn off the editor drawing of X-Particles own particles.

If you want to see them as well as the Thinking Particles display (the color and shape of those is taken from the Thinking Particles settings dialog) then check the Show particles switch in the Display tab.

Ensure Matching Coordinates

If you generate Thinking Particles, and show the X-Particles in the editor as well as the Thinking Particles, you will see that each Thinking Particle is separated by a slight offset from its corresponding X-Particle.

This is due to conflicting priorities of the emitter, the other generator objects in the X-Particles system, and Thinking Particles.

To get round this, enable this parameter setting.

This will ensure that the Thinking Particles and their matching X-Particles have the same coordinates, but you will see a lag between the emitter and any splines or objects produced by the xpTrail, xpGenerator, and xpSprite objects.

Note: If the offset between the two particle types is not a problem in your scene, it is strongly recommended that you leave this off.

If it is an issue for you, try turning it on and checking the effect on any other objects produced by the X-Particles system.

Ignore Particle Speed if Cached

Used when caching an emitter which generates Thinking Particles.

Add to TP Group

You can drag a Thinking Particles group from the Thinking Particles settings dialog.

Then the generated particles will belong to that group and take their visual appearance from the group settings.

Disconnect TP from X-Particles

Normally, X-Particles controls the position, speed and lifespan of the generated Thinking Particles.

They are, therefore, subject to the various X-Particles modifiers, actions, etc.

You cannot control the Thinking Particles with Xpresso or use the presets supplied with Cinema 4D.

If you want to generate Thinking Particles but let them be influenced by these other components then check this box.

When you do this, the X-Particles modifiers and control system will have no effect on the generated Thinking Particles.

In effect, the X-Particles emitter becomes a Thinking Particles emitter with certain additional capabilities, but missing some found in the Thinking Particles emitters.

Size

This setting is mostly used with the Proximal shader.

It influences the size of the effect of the shader.