Particle Systems Lecture Notes 3
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Make an emitter, play it then select the particles and connect them to a gravity field

Make a plane with Patches 4, 4 and scale it up - move it below the particles

Select the particles then shift select the geometry (plane)

Particles -> Make Collide

You can check out the connection in the Dynamic Relationships

Can set the bounciness on a per particle or per geometry basis
      Per Geometry - all particles bounce the same
      Per Particle - particles bounce differently

To set bounciness per geometry:
Select the geometry that the particles collide with

Open the Attribute Editor and select the GeoConnector tab

Set both Friction and Resilience to effect the bounciness

Resilience = how much rebound occurs
      Resilience - 0=no bounce, 1=fully rebound, pick a number between 1 and 0

Friction = how the bounces become less high each time it bounces on the surface
      Friction - 0= particles not effected by friction, 1=bounces straight off, pick # between 0 + 1

To set bounciness per particle:
Select the particles that collide with the geometry

      Open the Attribute Editor and go to the particleShape tab and Open Collision Attributes section

      Right click the Resilience or Friction attribute and Break Connection

      Enter a new value.

      Trace depth - how many times per frame it looks for collisions

Particle Collision Events
Make a new emitter and connect it to a gravity field

Make it collide with a plane

Select the particles and make a particle collision - Particles -> Make Collide

In Objects list of Particle Collision Event Editor: highlight Particles

      Set Event Name: Name it

      All Collisions - each time it collides it will do it

      Collision Number - only on the # bounce will it do it (e.g.. Collision Number 2 means only the second bounce is effected)

      Emit - ON = colliding particles emit new particles

      Split - ON = colliding particles split into new particles

      Random # Particles
            ON = will make a random Number of Particles
            OFF will look at Num Particles

      Num Particles - looked at by Emit and Split

      Spread - cone angle of area where particles are emitted - pick between 0 + 1, 1=180 degrees

      Target Particles - can specify existing particle group or new particle - will pick up the attributes from the specified particles

      Inherit Velocity - 0 = no velocity = no bounce; 1 = inherits all velocity = very bouncy
            pick a # between 1 + 0 and you will get diminishing bounces as it bounces

      Click Create Event
Setting an Initial State
Sets up the starting point for the simulation.
Rewind and go to the frame where the particles are like you want for the start of the simulation

      Select the particles you want to be effected

      Solvers - Initial State - Set for Selected - set it for the particles you have selected

      Set for All Dynamic - sets it for all particles
Changing the Starting Frame
Select the Particles -> Attribute Editor -> Time Attributes -> Enter Start Frame
or      keyframe the Emitter Rate to 0 then key it to emit at a later time
or      key the magnitude of the field to 0 then key it later to have magnitude
Combining Software and Hardware Particles
If you have hardware and software particles in the same scene, then you need to:

Add Dynamic Attributes to the software particles - Opacity

Add Per Object Attribute - Add Attribute

Set the Opacity to 0 while rendering the hardware particles and then set it back to 1 when rendering the software particles