Birth Script Example

Description

The following example shows the default Birth_Script script with detailed comments.

Can Be Used With:

This script is used as the default script in the Birth_Script action.

Effect:

The script generates a nice particle pattern - a helix built by a sine curve. In order to see the effect of the script, you should:

• Create a default PF_Source in the scene from the Create Tab of 3ds Max.

• Open Particle View

• Replace the Birth action with a Birth_Script action

• Delete the Speed, Position and Rotation operators.

• Scrub the Time

EXAMPLE

   --The ChannelsUsed handler defines the channels
   --to be made available to the script.
   --For the list of all channels, see
   --Interface: MaxscriptParticleContainer
   --The parameter pCont passed to the handler
   --contains the Particle Container the script is applied to
   on ChannelsUsed pCont do
   (
       pCont.useTime = true--enable the Time channel
       pCont.useAge = true--enable the Age channel
       pCont.usePosition = true--enable the Position channel
       pCont.useSpeed = true--enable the Speed channel
   )

   --The Init handler is called on initialization.
   --It is not used in this case.
   on Init pCont do
   (
   )

   --The Proceed handler contains the main script
   --applied to the Particles.
   --The parameter pCont passed to the handler
   --contains the Particle Container the script is applied to:
   on Proceed pCont do
   (
       --Get the Start Time as float. This converts the time to ticks.
       t1 = pCont.getTimeStart() as float
       --Get the End Time as float. This converts the time to ticks.
       t2 = pCont.getTimeEnd() as float

       --Clamp negative time values to 0
       if (t1 < 0) then
           t1 = 0
       --If the end time is less than 100 frames
       --(100 frames * 160 ticks per frame in 30 fps NTSC)
       if (t2 < 100 * 160) do
       (
           --then do a loop using the time values divided by 8
           --this way a particle will be created every 8 ticks
           for i in (t1/8+1) to (t2/8) do
           (
               --set the variable curTime to the actual time in ticks
               curTime = 8 * i as float
               --give birth to a new particle
               pCont.AddParticle()
               --get the index of the last particle that was added
               pCont.particleIndex = pCont.NumParticles()
               --set the current time of the particle in frames
               --(160 ticks in one frame at 30 fps NTSC animation)
               pCont.particleTime = curTime / 160
               --Set the age of the particle to 0 - newborn!
               pCont.particleAge = 0
               --Define a radius variable based on the sine of the current time
               sh = 2 * sin(5 * curTime)
               --Define an angle variable based on the current time
               ang = 0.2 * curTime
               --Set the particle position using the above variables
               pCont.particlePosition = [sh * sin(ang), sh * cos(ang), 0]
               --Define the speed using the same variables and falling down along Z
               pCont.particleSpeed = [0.01 * sin(ang), 0.01 * cos(ang), -0.005]
           )
       )
   )

   --The Release handler is used to do cleanup work.
   --Not used in this case.
   on Release pCont do
   (
   )