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Overview

Motion features provide movement to a component. Without a motion feature, particles will not be able to move even when a velocity is applied to them (see Velocity and Location for more details on how to add velocity to particles). Motion features can also use Effectors to apply non-uniform forces to the particles. Effectors are extremely important in adding flair to otherwise standard physics.

The following options are available under the Motion category:  

Collision

This feature allows particles to collide with and interact with the physical environment around them.

PropertiesDescription
TerrainAllows particles to collide against the terrain.
Static ObjectsAllows particles to collide against physical objects which cannot move, for example floors, walls etc.
Dynamic ObjectsAllows particles to collide against physical objects that can move, for example characters, vehicles etc. Note: That this method requires significantly more performance than either static Objects or Terrain. This option should only be used when strictly necessary.
ElasticitySpecifies elasticity for collisions (also affects bounciness). An elasticity value of 0 means particles will come to a stop at the instant of a collision. A value of 1 will make particles ‘bounce’ off the surface with which they collide.
FrictionSpecifies the friction coefficient when particles are sliding over surfaces. A value of 0 means particles are frictionless (i.e. a particle takes a long time before coming to stop), and where higher values mean more friction (i.e. particle takes less time before coming to a stop).
Collision Limit

Specifies if there is a limit to the number of collisions allowed:

  • Unlimited: Particles will collide against the physical environment as many times as is necessary.
  • Ignore: After reaching a certain number of collisions, particles will ignore any further collision(s).
  • Stop: After reaching a certain number of collisions, particles will stop. Even gravity cannot make particles move.
  • Kill: After reaching a certain number of collisions, particles are forcefully killed.
Maximum CollisionsThis option is active only when the Collision value is not set to Unlimited, this setting specifies the maximum number of collisions allowed per particle.
Rotate to NormalEvery time a particle collides, then it realigns its orientation to the surface it collided with.
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This feature is for CPU particles only. For GPU Particles, please refer to the GPU Particles Collision feature.
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The CryPhysics Motion feature already supports collisions and does not require this feature.

CryPhysics

This feature is a more advanced type of Motion physics. It uses CRYENGINE V CryPhysics to move a particle. It sacrifices the high levels of performance that Physics can provide, but is far more precise and better integrated with the physics scene. One of the most important aspects of this feature is that it allows the addition of mass to a particle and prevents the particle from being just points in space without any physical properties. This also implies that particles can carry momentum, and therefore, are not only affected by a level's physical objects, but a level's physical objects can also be affected by particles. This feature also enables particle collisions.

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This feature supports many of the systems provided by CRYENGINE V, but it comes with a significant cost in performance and is therefore not recommended to be used for more than a thousand particles or ideally less than a thousand (Motion Physics can handle dozens of thousands of particles in comparison, whereas GPU particles can handle hundreds of thousands of particles). It is recommended to mix up components with regular Physics and with CryPhysics using SecondGen Particles, this gives the best of both worlds.

Note: Only Point Particle collision detection is supported at the moment. Other types of collisions will be added later.

PropertiesDescription
Physics TypeLets you specify the following Physics type for a particle:
  • Particle
  • Mesh
Surface TypeSpecifies the physical material being used by the particle. For more information on Surface Types and Material Effects, see Material Effects.
Gravity ScaleScales the rate of acceleration due to the gravity level applied to particles. A value of 0 will disable gravity completely, while a value of 1 means full gravity acceleration.
DragAlso known as air resistance, specifies how much the particle's velocity should slow down in accordance to the air around them. This feature models linear air drag which means that the force applied to the particle is inversely proportional to its own velocity. This unit is measured in 1/seconds. The higher the value, then the faster particles will reach wind speed.
DensitySpecifies the density of a particle. This is in grams per milliliter (g/ml). The actual particle mass depends on its size and density. Larger particles will be heavier than smaller particles for the same density.
ThicknessSpecifies how much of the fraction of the particle's size is to be used as a collision radius. With a value of 0 only the center of the particle collides against the scene, while a value of 1 results in particles being simulated as spheres with a radius equal to particle size.
Uniform AccelerationApplies a uniform acceleration in meters per second squared (m/s2) that will be applied to all particles. This vector is added to the CryPhysics gravity acceleration, but is not scaled by the Gravity Scale property. A value of -9.8 in the Z axis will replicate the Earth's gravity.

MoveRelativeToEmitter

This feature moves the component's particles relative to its parent particle or emitter. Child particles will move whenever a parent has moved. This effectively stimulates local space particles and makes it much more search friendly.

PropertiesDescription
Position InheritWhile the parent particle is alive specifies how much of the parent's position is to be inherited.
Velocity InheritWhile the parent particle is alive specifies how much of the parent's velocity is to be inherited.
Angular InheritWhile the parent particle is alive specifies how much of the parent's orientation is to be inherited.
Velocity Inherit After DeathAfter parent dies allows child particles to inherit the last known parent's velocity.

Physics

Physics is the standard Motion type feature to move particles around. This feature has been constructed for high levels of performance, however it does sacrifice precision and interactivity with a scene.

PropertiesDescription
Gravity ScaleScales the rate of acceleration due to the gravity level applied to particles. The actual gravity acceleration and direction is specified in CRYENGINE V CryPhysics. AA value of 0 will disable gravity completely, while a value of 1 means full gravity acceleration.
DragAlso known as air resistance, specifies how much the particle's velocity should slow down in accordance to the air around them. This feature models linear air drag which means that the force applied to the particle is inversely proportional to its own velocity. This unit is measured in 1/seconds. The higher the value, then the faster particles will reach wind speed.
Uniform AccelerationApplies a uniform acceleration in meters per second squared (m/s2) that will be applied to all particles. This vector is added to the CryPhysics gravity acceleration, but is not scaled by the Gravity Scale property. A value of -9.8 in the Z axis will replicate the Earths gravity.
Uniform WindSpecifies a global wind velocity to be applied to all particles. This is added to the scene's wind velocity (See Level Settings for more details on how to setup global scene wind), but is not scaled by the Level's Wind Scale property.
Level Wind ScaleSpecifies how much global level wind affects particles (See Level Settings for more details on how to setup global scene wind). With a value of 0 particles will not be affected by global wind, but will be affected by other wind sources.
Angular Drag MultiplierAdditional scale multiplier on Drag to affect drag on spinning particles. When set to 1 Drag will affect spinning particles in the same way it affects moving particles. If set to 0 it will affect moving particles, but not their spin. Works for both 2D and 3D Spin.
Local EffectorsEnables the usage of the Effectors features that are being applied to particles. While Uniform Acceleration and Uniform Wind affect all particles equally, Effectors can specify different accelerations and wind velocities to each particle individually. This can enable quite sophisticated particle dynamics. For more information, see Effectors.

GPU Support

This feature is supported on the GPU, but no modifiers are available for the properties.

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