--- title: "Particle" url: "https://help.maxon.net/c4d/en-us/Content/html/OPARTICLE-ID_PARTICLE.html" section_path: "Simulate Menu > Particles (legacy) > Particle Emitter Object > Particle" element_id: "OPARTICLE" group_id: "ID_PARTICLE" description: "Defines how many particles per second are to be created in the viewport. The particles are emitted randomly from the entire surface of the emitter." --- ## Particle ### Birthrate Viewport Parameter ID: `PARTICLEOBJECT_BIRTHEDITOR` · Range: [0..1000000] Defines how many particles per second are to be created in the viewport. The particles are emitted randomly from the entire surface of the emitter. ### Birthrate Renderer Parameter ID: `PARTICLEOBJECT_BIRTHRAYTRACER` · Range: [0..1000000] Defines how many particles per second are to be created in the renderer. The particles are emitted randomly from the surface of the emitter. ### Visibility Parameter ID: `PARTICLEOBJECT_VISIBILITY` · Range: [0..100%] Defines how many of the particles should be visible. At first glance, this appears to offer no more than the birthrate settings. However, it is not possible to animate some of the parameters in the particle system, such as the birthrate settings. If you want to vary the intensity of the particle stream over time, animate the Visibility setting. ### Start Emission Parameter ID: `PARTICLEOBJECT_START` ### Stop Emission Parameter ID: `PARTICLEOBJECT_STOP` Use these values to define when (in frames) the particle emission should start and end. ### Seed Parameter ID: `PARTICLEOBJECT_SEED` · Range: [0..10000] Seed is used to create the pattern of the particle stream. If you copy an emitter, you will notice that both emitters generate exactly the same pattern. If you want each stream to be unique, set the Seed of each emitter to a different value. For example, a seed value of 1 will create a completely different stream than a seed value of 0. ### Relative Speed Parameter ID: `PARTICLEOBJECT_RELATIVE_SPEED` If this option is disabled, the particle's speed will be absolute and dependent on whether or not the Emitter is moving. If the defined particle speed is 100 cm/s and the Emitter moves with 500 cm/s in the direction of the particle emission, each particle will still only move at 100 cm/s. If this option is enabled, the defined speed will be added with that of the Emitter. For the aforementioned example, this would mean that the particles would move at 600 cm/s. This is a more precise and the particles will behave realistically. For example, if you were to throw a tennis ball out of a moving car, the tennis ball would also move at the speed of the car plus the velocity at which it was thrown. ### Lifetime Parameter ID: `PARTICLEOBJECT_LIFETIME` Gives the length of time a particle will be visible. For example, if flying sparks are set to be visible for 20 frames, the particles will disappear after this time. This value also controls the length of the animation Track in the Timeline. ### Variation Parameter ID: `PARTICLEOBJECT_LIFETIMEVAR` · Range: [0..100%] **Variation** adds a deviation factor to the Lifetime value; i.e., individual particles can live for a longer or shorter time, according to the size of the Variation value. ### Speed Parameter ID: `PARTICLEOBJECT_SPEED` · Range: [-∞..+∞m] Indicates the speed of the individual particles, in units per second. The higher you set the value, the longer the particle stream will be displayed in the viewport. > **Tip:** The speed can be set to 0. This can be useful if the emitter is animated, such as travelling along a spline, and you want the emitter to leave a trail of particles behind. Negative values can also be used. The emitter will then emit the particle stream in the negative Z direction. ### Variation Parameter ID: `PARTICLEOBJECT_SPEEDVAR` · Range: [0..100%] **Variation** introduces randomness to the speed. A value of 100% can make individual particles twice as fast, or twice as slow. ### Rotation Parameter ID: `PARTICLEOBJECT_ROTATION` · Range: [-∞..+∞°] Specifies the amount by which the particles will revolve around a spatial axis. ### Variation Parameter ID: `PARTICLEOBJECT_ROTATIONVAR` · Range: [0..100%] **Variation** adds a deviation factor to the value. ### End Scale Parameter ID: `PARTICLEOBJECT_SIZE` · Range: [0.00..+∞] Defines the final size of the particles relative to their starting size. A value of 0.5, for example, will shrink the particles to half their initial size. ### Variation Parameter ID: `PARTICLEOBJECT_SIZEVAR` · Range: [0..100%] **Variation** defines a variable factor for the scaling so that the particles are sometimes larger or smaller at the end of the animation. ### Tangential Parameter ID: `PARTICLEOBJECT_TANGENTIAL` If this option is disabled, the local Z axis of the individual object particles will always be aligned with the Z axis of the emitter. If the emitter orientation is animated, the local axes of each particle will be rotated if necessary to maintain this relationship. When Tangential is enabled, object particles are emitted with their Z axis aligned with the emitter's Z axis, but the orientation of each particle's local axis does not change as the emitter's orientation changes. ### Show Objects Parameter ID: `PARTICLEOBJECT_SHOWOBJECTS` If this option is disabled, the particles will be displayed in the viewport as lines. The direction and length of each line indicates the direction of flight and current speed of the respective particle — the longer the line, the faster the particle. If this option is enabled, the particles will be displayed in the viewport as objects (provided you have made an object a child of the emitter). This display mode can slow down the redraw rate considerably, especially when using complex objects as particles. ### Render Instance Parameter ID: `PARTICLEOBJECT_RENDERINSTANCES` Enable this option if the objects generated by the Emitter should be optimized with regard to memory usage, i.e., an almost infinite number of renderable [Render- und Multiinstanzen](https://help.maxon.net/c4d/en-us/Content/html/OINSTANCE-ID_OBJECTPROPERTIES.html.md) should be rendered.’