Proceed With Integrate Script Test Example


The following example shows the usage of the Inegrator interface in a Script_Test action.

Can Be Used With:

Should be used inside a Script_Test : Helper action.



Shows the necessity of using the Integrator. Without the Integrator particles are stopped somewhere around the zero Z plane. The Integrator is able to stop particles exactly at the plane level (without any modification of the particle position).

In the example flow, the particles are born and accelerated. The Script_Test checks their position and if they pass the scripted test, they are moved to the second event which stops them.

Sample File:



--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.usePosition = true --enable the Position channel

pCont.useSpeed = true  --enable the Speed channel



--The Init hander is called on initialization.

--It is not used in this case.

on Init pCont do





on Proceed pCont do


--Get the End Time

end = pCont.GetTimeEnd() as float

--Get the interface to the Integrator

_int = pCont.GetIntegrator()

--Get the current particle count

count = pCont.NumParticles()

--Get the particle container

pCont_curr = pCont.GetParticleContainer()

--Initialize Arrays

timeToStopInt = #()

timeToStopFloat = #()

particlesToStop = #{}

--Initialize a flag to signal when

--there are particles to send to the integrator

hasParticlesToIntegrate = false


--Go through all particles

for i in 1 to count do


--Set the current particle index

pCont.particleIndex = i

--Calculate the remaining time to travel

timeForTravel = end - (pCont.particleTime as float)

-- format "time to travel % = %\n" i timeforTravel

--Get the current position and speed of the particle

curPos = pCont.particlePosition

curSpeed = pCont.particleSpeed


--Calculate the time to the XY plane. Because of the minus sign,

--when the Z coordinate is negative, the time will be positive

timeToPlane = -curPos.z / curSpeed.z

-- format "time to plane % = %\n" i timeToPlane


--Initialize a flag

stopThisParticle = 0

--Get the particle time in frames

curParticleTime = pCont.particleTime as time


--If the time to plane is positive or zero and shorter

--than the time to travel, then the particle has passed

--the plane already and has to be stopped!

if ((timeToPlane >= 0.0) and (timeToPlane <=timeForTravel)) do


--Set the Test status to true

pCont.particleTestStatus = true

--Set the precise particle time

pCont.setParticleTestTimePrecise i pCont.particleTime timeToPlane

--Append the particle index to the BitArray of particles

--to be stopped

append particlesToStop i

--Raise the flag to signal there is work for the integrator

hasParticlesToIntegrate = true



--Append the particle time frame and fraction to the two arrays 

append timeToStopInt curParticleTime

append timeToStopFloat timeToPlane



--If the flag has been set 

if hasParticlesToIntegrate then


--If the integrator can be accessed, send the particles to stop

--to the Integrator

if _int != undefined then

_int.proceedASync pCont_curr timeToStopInt timeToStopFloat true particlesToStop


-- format "time to stop Int= %\n" timeToStopInt

-- format "time to stop Float= %\n" timeToStopFloat

-- format "part to stop Index= %\n" particlesToStop



--The Release handler is used to do cleanup work.

--Not used in this case.

on Release pCont do



See also

Using MAXScript in Script Actions

Particle Flow Sample Scripts