Hi Everyone
I am trying to write a script in 3DS which will calculate and output the distance each of the particles in the system have travelled.
So far i have a script that calculates the distance between two objects which is the basis for the entire script which would have the following logic…
- get position of particle in current frame and in previous frame
- calculate the distance between them (3d pythag)
- add this to a running total
- move to the next frame
The problem i am having is that i dont know how to access the individual particle’s position information (i only really need the calculated output for one particle) in order to do the appropriate calculations.
However, I am a complete newbie at maxScripting so if someone has a completely different take on how to achieve this then i am all ears!
Cheers
Stuart
I had to visualize the paths of particles recently, so I dumped the particle positions to an array, then built splines from the position data. You can easily get the length of a spline, so that might be a useful and flexible solition.
I wrote these functions:
function arrayToSpline arr =
(
-- spline
local ss = SplineShape pos:arr[1]
addNewSpline ss
-- knots
for i = 1 to arr.count do
(
addKnot ss 1 #corner #line arr[i]
)
updateShape ss
-- return
ss
)
function particleTrajectoryToArray pf pIndex =
(
local arr = #()
for t = 0 to animationrange.end do
(
pf.updateParticles pf t
append arr (pf.getParticlePositionById pIndex)
)
arr
)
So you just need to run something like this:
[left]
arr = particleTrajectoryToArray $pf 1
ss = arrayToSpline arr
curveLength ss
[/left]
It wouldn’t be 100% accurate but how about:
function particleTrajectoryToArray pf pIndex =
(
pdist = 0
local prevloc
for t = 0 to animationrange.end do
(
pf.updateParticles pf t
if t != 0 do pdist += (distance prevloc (pf.getParticlePositionById pIndex))
prevloc = (pf.getParticlePositionById pIndex)
)
return pdist
)
Thank you guys very much! That is fantastic.
Ive tested it and modified it a wee bit to suit and its looking great – especially the spline drawing bit, i hadnt thought to include something like that but it will be a great addition to visualize the movement.
One more thing however, is there a way to get the number of particles emmitted so i can loop through them all and get the data for each of them, without having to input the indexes individually. I know i could just loop through the number i know i have set but it seems very clumsy and not very portable so i’m sure there is a way!
Thanks again, much appreciated
Stuart
Hey Stuart,
Happy to help =)
You know all this information is in the MaxScript help, don’t you? Look at the last but 1 topic in the contents, MacScript Extensions, then the Partice Flow topic, and it’s all in there. Might take some getting to know, but it is all there.
In the meantime: $pf.numParticles()