Properties

Lifetime

Limited

By default, this option ensures that the particles are not created with a lifetime limit, i.e., they are not automatically deleted again after a certain period of time. However, if you need the particles to disappear automatically, activate this option and use the following Expectation setting to define a lifetime limit. In any case, the lifespan can still be influenced after emission, e.g., via modifiers or a Destructor Force object.

Expectation

This value, measured in frames, specifies the period of time after which the particles should be automatically deleted. This time period used applies from the moment a particle is created. The lifetime can also use a Variance that gets applied randomly per particle. In addition, the lifetime of the particles can be individually extended or shortened by modifiers even after emission.

Variance

This value given in frames can be used to randomly vary the life expectancy of the particles. This can result in an extension or shortening of the original Expectation by a maximum of the entered value for each particle. Like all variation values, this setting is also based on the Seed value of the emitter. A new Seed value therefore also results in a redistribution of the Variance for the length of the life span of the particles.

Lifetime Map

You can assign a Vertex Map here. Their values are multiplied by the Lifetime Expectation setting to determine the actual lifetime of the particles.

Velocity

Speed[-∞..+∞m]

This is the distance that the particles should travel within one second. This speed can be varied randomly for each particle via the Speed Variance or subsequently influenced via modifiers and forces.

If the option for Show Handles has been activated, this value can also be edited interactively directly in the view by dragging one of the handles. The Use Model Mode must be active for this. The handles can then be moved - as with the parametric primitive objects - using the Move Tool, for example. The corresponding handle can be seen at number 1 in the following illustration. If the handles for digit 2 are not yet visible, you can hold down the Shift key and drag the Speed handle or configure a Speed Variance above 0. The Speed Variance can then also be set interactively by moving the digit 2 handles with the mouse if the Enable Variance option is also active.


Both the speed of the particles (see handle 1) and the variation of this emission speed (see handle at number 2) can be set interactively in the views.

In addition to these handles - depending on the selected Direction mode for the direction of flight of the particles - additional auxiliary lines are sometimes displayed, which mark the distances covered by the particles within one second. In the following illustration, you can see these brown radii as examples for the Direction settings Radial, Random and Custom.


From left to right, the range markers for the Direction modes Radial, Random and Custom.

Enable Variance

Activate this option if you want each particle to have a random deviation from the average Speed. The maximum speed deviation for the particles can then be specified via the subsequent Variance value.

This option also ensures that additional handles can be used directly in the views to adjust the speed variation interactively with the mouse. In order for these handles and guides to be visible, the Show Handles option must also be active.

Variance[-∞..+∞m]

This value represents the maximum change in velocity and can therefore be used to randomly reduce and increase particle velocities during emission. Like all variation values, this setting is also based on the Seed value of the emitter. A new Seed value therefore also results in a redistribution of the Speed Variance on the particles.

The Speed Variance can also be configured interactively by dragging the handles in the views, as shown in the illustration above. In order for these handles to be displayed, the option for Show Handles must also be active. If these handles are not visible despite the Enable Variance option being active, hold down the Shift key and drag the handle for the Speed of the particles. The handles marked with the number 2 in the figure above always move symmetrically, so it does not matter which of the two you move. The handle closer to the emitter shows the smallest, the handle furthest away shows the maximum speed of newly emitted particles.

Speed Map

You can assign a Vertex Map here. Their values are multiplied by the Speed setting from the Properties settings to ascertain the actual start speed of the particles.

Direction

Use this setting to define the directions in which the particles emerge from the Emitter. The following options are available:

  • Axis: Use separate buttons for the desired axis direction to select the initial direction of the particles. The Space setting can also be used to select whether it should be the local axis of the Emitter or the direction of a world axis, in which case the orientation of the Emitter is no longer important.
  • Normal: The particles are emitted in the direction of the surface normal. In the case of two-dimensional Emitters, this will result in a more or less pronounced emission in one direction (an additional deviation from this direction can be achieved via the Spread angle). With volumetric Emitter shapes, the particles are emitted on all sides.
  • Radial: With two-dimensional emitter shapes, the particles are emitted outwards in a circle in the XY plane of the emitter. The axis system of the Emitter is used with Space Local, otherwise the XY plane of the world is used with Space Global. Without using Spread, a disk-shaped output is created. With three-dimensional Emitters, the particles are emitted in a spherical shape.
  • Random: The direction in which the particles are emitted is purely random and therefore independent of the selected Emitter shape.
  • Target: You can define an object at whose position the travel directions of the particles are aimed. As can be seen in the following illustration, this automatically adjusts the direction of the Speed handle so that it is aligned with the assigned Target Object (shown here as a reddish star). This means that the direction in which the particles are emitted can be guessed even if the Target object is not currently visible in the view.


  • Custom: You define any direction vector that controls the direction in which the particles are emitted. This Vector is automatically normalized and therefore does not affect the speed of the particles. The direction can be interpreted either in the axis system of the emitter or globally.
    This vector can also be adjusted interactively with the mouse in the views. The Model editing mode must be active for this. The handle can then be moved - as with the basic parametric objects - using the Move tool, for example. Simply pull on the corresponding handle to rotate horizontally. By additionally holding the Shift key while dragging the handle, it can be moved vertically.


    In the case of the number 1, the Direction handle can be seen here. This can be moved along spherical paths around the emitter in order to change the direction in which the particles are emitted. By holding the Shift button, you can switch between horizontal and vertical rotation of the direction vector.

Axis

When selecting Axis Direction, select the axis direction in which the particles are to be emitted. The following Space setting then defines whether axes of the Emitter or world axes are meant.

Vector[XYZ m]

Here you can define your own direction vector when selecting Direction Custom. By using the Space setting, this vector can be evaluated in the axis system of the Emitter or also relative to the world axes.

As already explained in the explanation of the Direction menu, this vector can also be adjusted directly in the views by moving a handle. All you need to do is activate the option for Show Handles.

Vector Space

The reference system can be selected here for the Axis, Radial and Custom Direction settings. With Local, the evaluation is carried out in the axis system of the Emitter; with Global, the world axes are used.

Target

After selecting Direction Target, any object can be assigned here using drag & drop, to whose position the emission directions of the particles should be aimed.

Spread[0..360°]

A maximum deviation from the particle emission direction defined by Direction can be selected here.

Spread Falloff[0..100%]

This value controls the relationship between the direction varied by Spread and the original emission direction of the particles. The greater the Spread Falloff, the closer the emission angles of the particles return to their original direction. The greatest possible scattering of the particle flight directions is therefore obtained with a value of 0%.

Direction Map

As a vector is required for the direction of flight, only one Vertex Color Map can be assigned here. Their red, green and blue components are interpreted as X, Y and Z directions. Since the color values can only be positive by default, only directions along the positive axis directions can be implemented. However, you can use the subordinate Mix setting to smoothly mix between the originally selected flight direction and the direction specified via the Vertex Color Map.

Remember that the direction can be interpreted both locally in the axis system of the geometry and relative to the world axis system. The corresponding option can be found in the Properties settings of the Emitter.


A Field was used here to calculate a Vertex Color Map. A pure green color leads to a particle movement along the positive Y-axis. In the area with the purple color, a maximum blue value and a maximum red value were combined, resulting in a direction of movement centered between the X and Z axes.

Mix[0..100%]

This controls the influence of the Vertex Color Map used to control the flight direction.

Add Emitter Velocity[-∞..+∞%]

By default, the Emitter only determines the location of the particle birth and its properties. There is therefore no correlation between an animation of the emitter position and the properties of the particles, for example. However, this can be changed with higher values for this setting. With larger percentage values for Add Emitter Velocity, the movement or rotation of the Emitter can also be transferred to the starting speeds of the particles, as shown in the following video.


The video shows two randomly oscillating Emitters. The upper Emitter does not use any addition of its transformation velocity to the particle velocities, the lower Emitter has this activated 100%. Note how particles can be emitted towards the rear of the Emitter surface, e.g. by a rapid backward movement of the Emitter.
Expanding the small arrow in front of the parameter gives you access to the settings for Linear and Angular, which can also be used to control the effect separately for position and rotation changes.

Linear[-∞..+∞%]

Angular[-∞..+∞%]

When using Add Emitter Velocity, you can separately adjust the individual influence of position changes(Linear) and rotation changes(Angular) on the emitter on the particle speeds.

Alignment

Each particle contains a complete axis system and can represent not only a position, but also rotations and orientations. This is important so that, for example, a flock of birds can be animated with particles, in which all birds automatically fly head-first and are aligned appropriately. The alignment of the particles can also be automatically adjusted during the flight through space using the Look Modifier, for example, so that a specific particle axis always points in the direction of flight. Here, however, the focus is on the initial orientation of the particles at the moment of their birth at the Emitter.

Forward Vector

Various modes are available here for selecting how the axis systems of the particles are to be aligned. The Z-axis of the particle systems is generally aligned. The Y-axis direction of the particles can then be affected indirectly via an Up Vector, which ultimately leads to a stable alignment of the particles:

  • Axis: Any axis direction of the Emitter or the world system can be used for alignment.
  • Velocity Direction: This is often the desired mode in which the particles are automatically aligned according to the direction of emission at the Emitter.
  • Normals: The particles are aligned parallel to the normals of the Emitter shape.
  • Radial: The imaginary connecting line between the center of the Emitter and the position at which a particle is created is used for alignment.
  • Random: The alignment is based only on the Seed value of the Emitter and is random for each particle.
  • Target: The particles can be aligned to the position of an assigned target object.
  • Custom: You can specify a Vector yourself that is to be used to align the particles.


Examples of different orientations, illustrated by the use of axis systems for the particles. On the left the use of the velocity vector, in the center a radial alignment and on the right random alignments for the particles.

Axis

For Forward Vector Axis, the desired axis direction can be selected here. The separate Vector Space setting is used to specify whether the axis system of the emitter or the directions of the world axes are meant.

Vector[XYZ ]

With Forward Vector Custom, the desired direction can be selected here; the separate Vector Space setting determines whether this direction vector is to be interpreted in the axis system of the emitter or in the world system.

Vector Space

The reference system can be selected here for the Axis, Radial and Custom Forward Vector settings. With Local, the evaluation is carried out in the axis system of the Emitter; with Global, the world axes are used.

Target

Any object can be assigned here using drag & drop, and the Z axes of the particles will then continuously target its position.

Spread[0..360°]

A maximum deviation from the particle orientation defined for the Forward Vector can be selected here.

Spread Falloff[0..100%]

This value controls the relationship between the orientation varied by Spread and the original Forward Vector of the particles. The greater the Spread Falloff, the closer the alignment of the particles approaches their original direction again. The greatest possible spread of particle orientations is therefore obtained with a value of 0%.

Up Vector[XYZ ]

The Z-axis of the particle axis systems is determined by the settings for the Forward Vector. However, the directions for the X and Y axes will still remain. Without further specifications, the axis system of the particles could therefore rotate uncontrolled and freely around its Z-axis, which would make a stable alignment of the assigned particle shapes impossible. Therefore, this specification of a further direction is used for the alignment of the Y-axes on the particles. This directional information is not necessarily taken over completely by the Y-axis of the particles, but it helps to calculate a stable position in space. You can imagine this Up Vector direction as a magnet that pulls the Y-axis of the particles in its direction and thus stabilizes the position of the particle axes, while the Z-axis of the particles always follows the Forward Vector specification absolutely. The remaining direction of the X-axis on the particles then results automatically from the specification that all three axes are always perpendicular to each other by default.

Technically speaking, the Z-axis of the particles is defined by the direction of the Forward Vector. To determine the X-axis, a vertical vector is then calculated on the plane that runs through the Forward Vector and the Up Vector. The missing Y-axis results automatically from the condition that all three vectors must be perpendicular to each other.

Forward Map

This lets you control the alignment of the newly-created particles individually using a Vertex Color Map. The red, green and blue values of the Vertex Color Map are interpreted as the X, Y and Z components of a direction vector to which the Z axis of the particles should be aligned. As the color components of the map are only defined as positive, only positive axis directions can be used.

Remember that the orientation can be interpreted both locally in the axis system of the geometry and relative to the world axis system. The corresponding option can be found in the Properties settings of the Emitter.

Mix[0..100%]

This controls the influence of the Vertex Color Map used to control the particle alignment.

Angular Velocity

These settings can be used to control the intrinsic rotation of the particles. The direction of movement remains unaffected. As already mentioned in the settings for the alignment of the particles, only the initial rotation of the particles is defined at this point, which is applied at the time the particles are created. How the rotation should be changed after the particles have been created must be implemented separately using Modifiers such as Spin.

Speed[-∞..+∞°]

This controls the speed of the rotations. This is defined as the angle of rotation, which is evaluated per second. A value of 360° therefore leads to a complete rotation of the particles around the separately specified Spin Vector per second of the simulation.

Speed Variance[-∞..+∞°]

This specification is used to randomly vary the rotation speeds of the particles. The value indicates the maximum deviation from the specified peed. As with all variation values, this is also based on the Seed value of the emitter. A new Seed value also leads to new variations for the particle rotational speeds.

Angular Speed Map

You can assign a Vertex Map here. Their values are multiplied by the Speed setting from the Angular Velocity settings of the Properties tab to define the actual rotation speed of the particles.

Spin Vector

  • Axis: You specify one of the particle axes, an axis of the Emitter or one of the global axis directions for the rotations.
  • Velocity Direction: The particle rotation takes place around the direction of travel of the particles. This would be, for example, the usual direction of rotation for a projectile that is stabilized by this rotation during flight.
  • Normal: The surface normal of the Emitter specifies the axis of rotation for the particles. In the case of three-dimensional Emitter shapes, there is therefore a variation in the axes of rotation, depending on where a particle is created.
  • Radial: The axis of rotation runs through the center of the Emitter and the emission position of each particle.
  • Random: The axis of rotation is defined randomly for each particle. As with all randomness, this calculation is also based on the Seed value of the Emitter. A change in the Seed value therefore also leads to a recalculation of the axes of rotation.
  • Target: Here you can link any object whose position is evaluated. The direction between each particle and the defined object position is used as the axis of rotation.
  • Custom: You can define any Vector to be used as the rotation axis. The length of this vector is irrelevant. The vector can be evaluated either in the system of the particle, in the system of the Emitter or in the global world system.

Axis

For Spin Vector Axis, the desired axis direction can be defined here. The Vector Space setting is also used to specify whether the axis system of the particle, the emitter or the directions of the world axes are meant.

Vector[XYZ ]

For Spin Vector Custom, the direction of the desired rotation axis can be entered here. The separate Vector Space setting is used to specify whether this direction vector is to be interpreted in the axis system of the particle, the emitter or in the world system.

Vector Space

The reference system can be selected here for the Spin Vector settings Axis, Radial and Custom. The particle matrices' own axis system is used for Alignment. With Local, the evaluation takes place in the axis system of the Emitter; with Global, the world axes are used.

Target

Here you can use Spin Vector Target to assign any object whose position is evaluated using drag & drop. The imaginary connecting line between each particle and the specified object position is used as the axis of rotation.

Spread[0..360°]

Here you specify a maximum direction variation for the axes of rotation. As with all random variation values, this calculation is also based on the Seed value of the emitter. A new Seed value therefore also leads to a new variation of the axes of rotation.

Spread Falloff[0..100%]

This value controls the ratio between the rotation axis of the particles varied by Spread and the original Spin Vector of the particles. The greater the Spread Falloff, the closer the rotational axes of the particles return to their original direction. The greatest possible spread of the rotational axis directions is therefore obtained with a value of 0%.

Spin Vector Map

This lets you control the direction of the rotation axis for the newly-created particles individually using a Vertex Color Map. The red, green and blue values of the Vertex Color Map are interpreted as the X, Y and Z components of a direction vector around which the particles are to rotate. As the color components of the map are only defined as positive, only positive direction vectors can be implemented.

Remember that the axis of rotation can be interpreted both locally in the axis system of the geometry and relative to the world axis system. The corresponding option can be found in the Properties settings of the Emitter.

Mix[0..100%]

This controls the influence of the Vertex Color Map used to control the particle rotation axis.

Color

In this area, you define the start color of the particles and their Alpha value. This Color is read out automatically, e.g. by the MoGraph Cloner or the Redshift Object Tag. In addition, this particle color can also be read directly via a Color User Data Node in Redshift materials. The Alpha value of the particles can be read out separately via a Scalar User Data Node.

Sample Mode

Here you can select how colors are to be generated and assigned to the particles:

  • Constant: The values set with Color and Alpha are assigned to all particles. This is the default setting.
  • Random: In this mode, an individual color gradient with colors and alpha values can be defined. The colors and alpha values are then read out randomly from this gradient for each particle.
  • Noise: This mode works in a similar way to Random and also uses an individually configurable color and alpha gradient. This time, however, the assignment of colors and alpha values is not purely random, but based on common noise patterns and can therefore also be configured with transitions.


On the left is an example of the Constant color assignment, in the middle a Random color assignment and on the right a color assignment based on a Noise structure.

Color

In Constant Sample Mode, select the color value that should be assigned to all particles when they are created. Click on the arrow symbol next to the color field to access the standard color controllers and color selection systems. Alternatively, different color selectors can also be displayed in a separate dialog box when clicking directly on the color field.
The pipette symbol to the right of the color field also allows you to pick up a color value directly from another location on your monitor with a simple left-click. This color recording mode can also be ended early by pressing the Esc key.

Alpha[0..100%]

In Constant Sample Mode, select the alpha value that should be assigned to all particles when they are created. This property is not displayed directly on the particles in the viewports, but can be read out, for example, within Redshift materials with the Scalar User Data Node and its Particles/Transparency (XP) preset and thus also used to control material properties. Its use is not limited to specifying the color opacity, but can also control the roughness of a reflection or the intensity of lights, for example. This is because an Alpha value represents regular floating point values between 0 and 1 (or converted values between 0% and 100%).

Color Map

If you want an individual color distribution of the particles on the Emitter, you can assign a Vertex Map or a Vertex Color Map here. The latter has the advantage that you can, for example, paint any color values directly onto a surface using the Paint Tool from the Tools menu. As these colors are stored per point on the surface, no UV coordinates are required on the geometry. Here, too, there is a separate Mix slider, which will be made visible after clicking on the arrow next to the field for the color map.

Mix[0..100%]

This controls the influence of the Color Map used to control the particle colors.


On the left 0%, in the middle 50% and on the right 100% were used for the mixing value of the color map.

Gradient

This element is offered in the Random and Noise Sample Modes and allows you to specify several color and alpha values from which values are then selected randomly or based on a noise structure and used for the particles. The color gradient used for this is also used as a control element in many other places in Cinema 4D. If you would like to read about its functions again here, simply open the following section.


Noise

These settings are only used in the Noise Sample Mode. The selected Noise pattern generates black and white values that are used to read the matching entries from the color gradient. With a black section in the Noise, the colors and alpha values from the left edge of the color gradient are used for the particles; with white Noise, the colors and alpha values from the right edge of the gradient are used. Gray intermediate values address corresponding sections in the middle part of the gradient.

Noise Enabled

This option must be switched on so that a Noise structure is used to determine the color and alpha values of the color gradient. If this option is switched off despite the selection of Sample Mode Noise, all particles will receive the same color from the left edge of the gradient.

Seed[-2147483648..2147483647]

The calculation of the Noise pattern is based on this value. A change in the Seed value therefore also leads to a recalculation of the selected Noise structure.

Noise Type

Here you can choose the right one from the various patterns. These are three-dimensional structures that can be configured in the axis system of the emitter or the world and with individual scaling along all axis directions. Automated modification and animation of these patterns is also possible:


Noise Space

Here you can select whether the Noise structure should move with the axis system of the emitter or whether it should be a stationary Noise whose origin lies in the global world axis system.

Octaves[1.00..20.00]

This defines the amount of detail in the Noise structure. Larger values produce more variations in the Noise pattern. Small values lead to a loss of contrast and details, as well as to a softening of the structure. This setting is not available for the Noise Types Box, Cell, Mod Noise, Perlin and VL Noise.

Relative Scale[XYZ %]

You can use these values to scale the Noise structure individually along the three spatial directions. Proportional scaling is also possible via the separate Scale value.

Scale[-∞..+∞%]

This allows the Noise structure to be scaled proportionally. Individual scaling for each of the three axis directions is also possible using the separate Relative Scale.

Animation Speed[-∞..+∞]

The Noise structures can also be changed over time. Use this value to specify the speed of these changes. By default, 0 is used here, which results in a static structure.

Loop Period[0.00..+∞]

Almost all Noise types (exception: Electric and Gaseous) have this parameter, which causes the noise to loop after the specified time in seconds (the Animation Speed must be greater than 0). The Noise state then repeats itself in the bars of the Loop Period, which is specified in seconds. A value of 0 turns this effect off.

Movement[XYZ m]

Speed[-∞..+∞%]

These two parameters are used to move the Noise through the 3D space. Movement is used to set the direction in which the Noise structure is moved. Use the Speed value to regulate the movement speed of the Noise structure.

Please note that the Movement is also dependent on Noise Space, as the coordinate systems defined there can differ greatly from one another.

Low Clip[0..100%]

High Clip[0..100%]

This can be used to limit the brightness values that the Noise should provide. By default, Low Clip is 0% and High Clip is 100%. This means that all brightnesses can be output unchanged between 0% and 100% by the Noise. Increasing the Low Clip results in all brightnesses that are lower than Low Clip being output as black (or 0%). Similarly, a reduction of High Clip results in all gray values above the brightness of High Clip already being output as white (or 100%).

In fact, this mechanism can be used not only to sharpen a Noise structure and to strengthen the contrast, but also to invert the brightness values. To do this, simply reverse the original arrangement of the clipping values. With Low Clip 100% and High Clip 0%, you get an inverted noise.

Brightness[-100..100%]

This is used to adjust the general brightness value of the Noise. Values above 0% increase the brightness, values below 0% reduce it.

Contrast[-100..100%]

This allows us to reduce or increase the contrast of the Noise brightnesses. The Contrast describes the range of brightness values output. With a low contrast, the differences between the Noise brightnesses supplied are therefore smaller. Greater Contrast leads to greater differences in brightness between the Noise brightnesses calculated. This often results in the brightness transitions being more abrupt and less smooth compared to using a lower Contrast.

Radius

Radius[0..+∞m]

This regulates the scaling of the particles. The size of the particles can also be displayed directly in the editor if you have activated the option to draw the radius in the Particle Group. The Radius of a particle is also automatically used for scaling the shapes that are bound to the particle via a Redshift Object Tag, for example.
The Radius can also be varied per particle during emission with the following Variance value. It is also possible to adjust the Radius at any time using various particle modifiers.

Variance[0..+∞m]

Here you can define a maximum deviation from the defined radius per particle. Negative radii will automatically be avoided for the particles. Particles can therefore never have a negative radius.


Here, a Radius of 1 was combined with a Variance of 5. This results in particles with sizes between 0 and 6.

Radius Map

You can assign a Vertex Map here. Their values are multiplied by the Radius from the Properties settings to determine the actual radius of the particles. The following video shows an example of this. There, the radii were controlled with a random field in a Vertex Map.