Vorticity Particles
Vorticity particles have the purpose of providing the user with a particle system that is passively advected by a velocity field (fluid dynamics) and which is specifically used with the Particle Turbulence force to generate physically-based vorticity/turbulences in a fluid flow.
Vorticity Particles::Display
Draw each Xth particle
Allows to set an interval for drawing particles. A value of 0 will turn off the display of particles.
A value of 1 will display all particles, a value of 2 will draw each second particle and so on.
Color
The display color of this particle type.
Size
This option, if set > 0.0, will create for each particle a sphere render instance of the specified size.
Advection
Defines how the particles are advected.
Off
No advection takes place. Use this if you want to have static particles or if you want to advect them yourself.
Dynamics
Advection is done by an external velocity field (fluid dynamics).
Ballistic
Ballistic advection. No reaction to fluid dynamics and/or grid forces. Particle forces can directly be used on them though.
Dynamics & Ballistic outside
Advection is done by an external velocity field (fluid dynamics) if the particles are inside of a fluid container domain.
Outside of it, the particles switch to ballistic advection. This allows to have the particles keep on moving outside the grid domain.
Advect by Fluids
If the particles are inside of a gaseous fluids domain, they are advected by the according velocity field.
Advect by Liquids
If the particles are inside of a liquid fluids domain they are advected by the according velocity field.
Volume Collision
Defines the collision with any volumes in the Effex scene.
Off
No collisions are calculated
Obstacles
Collides with all volumes that have an obstacle tag attached. You would use this mode if you don't have any fluid dynamics in the scene and/or the particles are ballistic.
Obstacles (Fluid Dynamics domain)
Collides with the obstacles field defined inside of a fluid dynamics domain (the fluid dynamics generate an optimised version of all obstacles in the effex scene
so collisions can be calculated faster.
Instants
Instants are evaluated when a certain event takes place. In this case the particle-volume collision event will trigger instant operators.
Drop any instant operators in here to let them do their thing on particles when they do collide.
Kill outside containers
If particles leave a used fluid dynamics container, this setting (activated) will let the particles die instantly.
Integrator
Defines how the advection (moving the particles around inside the grid based on the velocity field) in time and space is integrated.
The higher the order number, the more accurate the integration will be.
In order of quality:
Euler 1st Order
Runga-Kutta 2nd Order
Runga-Kutta 3rd Order
Runge-Kutta 4th Order (best)
Ballistic Integration
Defines how the ballistic advection (moving the particles around according to any external particle forces) in time and space is integrated.
Euler
Advects particles using a special Euler intergrator. This integration is based on the position and velocity of the particles.
Any available external force property is also taken into account.
Verlet
Advects particles using a Verlet integrator. This integration is based on the position of the particles only. This is the same integrator
that was used for the former Simple Particles.
Advection Substeps
How many substeps should be taken per advection step. Can improve accuracy.
Exclude & Fluid Dynamics
The drop down lets you decide if the below Fluid Dynamics list and any of its entries are excluded or included from being used in the particle advection step.
Particle Forces
Drop in here any Particle Forces or Dual Forces that shall act on the particles in this subgroup.