5D.Particles

Exercise 1: A SIMPLE PARTICLE SYSTEM

basic stream of particles

 

1. load Particles
2. use an empty clip for the background; only one input clip is needed for this experiment
3. extend the length of the clip to 100+/- frames
4. set up the shuttle to cover the fx
5. open a monitor
6. go to frame 0
7. open the time editor
8. set Position Y Center to 80.0
9. set Position Radius to 5.0
10. set Forces Velocity Strength to 0.0
11. set Forces Gravity Strength to 30.0
12. pop up the PI
13. click on KILL ALL PARTICLES
14. select streaks so you can see more easily the movement
15. play through the sequence
    • A stream of particles is born and falls downwards. Notice how they start to move faster and faster as they fall. This is the effect of Gravity.

16. rewind and play again. The previously created particles still exist. All particles continue to exist until they die naturally or are killed.
17. rewind, turn on KILL ALL PARTICLES, and play again. All the original particles are killed and a completely new set is created.
18. set Friction to 5.0
19. click on KILL ALL PARTICLES
20. play the sequence again
    • The particles still fall but they do not accelerate so fast as friction is gradually reducing the effect of gravity. This is not the same as reducing gravity and not using friction.

INFLUENCES IN EXERCISE 1

• GRAVITY:
  • Initially the only force acting on the particles is gravity. The particles fall down, accelerating under influence of gravity. Increase gravity to speed up the particles and reduce the gravity to slow them down. At a gravity of 0.0 there will be no gravity influencing the movement.
  • The direction that gravity acts can be changed with gravity angle, measured in degrees with 0 degrees acting to the right, 90 upwards, 180 to the left and 270 downwards. Any direction can be specified between 0.0 and 360.0.
• FRICTION:
  • Friction can be used to slow the descent of the particles. Gravity will drag them downwards accelerating until the frictional force balances gravity.
  • A strong frictional force can be very useful to keep the particles swirling together.
• BIRTH:
  • The default fecundity or particles born each frame, is set quite low at 50 with a random variation, fecundity varariance, each frame of +/- 10. While you are setting up a sequence use low numbers for speed.
  • The region of birth starts from the X/Y position and extends in a circle, as far as radius allows.
• LIFETIME:
  • Each particle can live for a defined number of frames, lifetime, which can be randomly augmented by lifetime variance. The instant each particle is born it starts to die or fade away, controlled by extinction and extinction varariance. If extinction is less than lifetime the particles will fade away before they disappear. If extinction is much greater than lifetime then there will be no noticeable fading and the particles will pop off.
• VELOCITY:
  • There is no velocity given to the particles at birth in this first example
  • You can add an initial force to them:
    • set the Velocity Strength to 10.0
    • set Gravity to 0.0
    • set Friction to 0.0
    • click on KILL ALL PARTICLES
    • play the sequence again.
    The particles fly upwards.

  • Velocity angle sets the direction of the movement in degrees ( cf gravity).
  • Try changing Velocity Scale to 170.0, Velocity Magnification Variance to 40.0 and Velocity Direction Variance to 45.0 to add variance to speed and direction of movement.

By combining opposing forces you can throw the particles up in the air and watch them fall down again.

• set Position Y Center to 50.0
• set Position Radius to 1.0
• make Lifetime and Extinction around 200 frames each
• set Velocity Strength to 10.0.
• set Velocity Scale to 300.0.
• set Velocity Angle to 90.0 (upwards).
• set Velocity Magnification Variance to 40.0
• set Velocity Direction Variance to 15.0
• set Gravity to 30.0
• set Friction to 0.0.
• KILL ALL PARTICLES
• play the sequence again
• try increasing Friction

Index