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Thruster particle simulation
show user profile  Davesbeard
Hi guys, i'm doing a research project on the design of a target for testing of an ion thruster at the University of Southampton. The purpose of the target is to prevent particles bouncing back towards the thruster potentially damaging it. I'm using 3ds max as a way of doing a basic model of the thruster and the target. In order to determine how effective each target is i need to be able to quantify how many particles are being bounced back to the thruster. So far the only way i can think of doing this is counting the returned particles myself. Firstly is there any way of making the particles change from say a dot to a cross once they have impacted with the target? Secondly and this may just be wishful thinking, is there any way of getting 3ds max to count the particles going past a certain point? That way i could just count any particles that make it to the thruster area.

Hopefully that makes sense! Haha. Any tips would be greatly appreciated :)
read 1241 times
2/5/2009 9:05:04 AM (last edit: 2/5/2009 9:05:04 AM)
show user profile  Dr. Jim

You can put a delfector as your 'threshold'....then pipe the partilcles that cross the threshold into a new event that changes their shape or color or relocates them somewhere else or whatever.
That part should be quite easy enough. As far as counting them goes,....I am sure there is a simple way to do that too....just not sure what it is off top of head....

btw - I assume you are using Pflow?

read 1236 times
2/5/2009 9:18:07 AM (last edit: 2/5/2009 9:18:07 AM)
show user profile  parkerfamily
call the maxscript experts of the forum. that would be my bet for the particle counting.
read 1192 times
2/5/2009 6:45:02 PM (last edit: 2/5/2009 6:45:02 PM)
show user profile  killerbee2
if you want quasi accuracy check out xflow.

read 1186 times
2/5/2009 7:25:10 PM (last edit: 2/5/2009 7:25:10 PM)
show user profile  Davesbeard
Cheers for the input guys but i think that i may have jumped ahead of myself tbh. I assumed i'd be able to get the basic setup sorted problem free but apparently not.

I've set up my thruster exhaust particle system pretty much how i want it using Super Spray and now i'm trying to get the particles to interact with the test chamber and a target. I've tried using Udynaflect, binding one to the chamber, one to the particle system and one to the target but i can't seem to get them to interact. The particles still go straight through. Any tips?

Also, is Super Spray a good choice or will it make counting the particles more difficult later?
read 1123 times
2/9/2009 9:59:23 AM (last edit: 2/9/2009 9:59:23 AM)
show user profile  Toen
Hey Davesbeard,
I would use particle flow for this, would make it easier.
With particle flow you can cause the particles to go into different events according to the criteria you set up. For example after you set up the proper deflectors for deflecting and catching particles, you could send all of the caught particles to a particular event and then use 3ds Max to count the particles in that event for you by going to 'Selection > Event button' in the Modify panel of the Particle Flow object. You should see a list of events to choose from in the resulting rollout. Whichever event you select will cause that particles in that event to become highlighted/selected and also counted as well.

With Pflow you can have one test that tells particles hitting a particular deflector to bounce off of it, and then have another test that tells particles that hit another particular deflector to stick to it (the caught particles). Then you could then direct those caught particles into their own event, to be counted, have their shape or color changed, etc.

I can make a working example of this if you want to help to better understand it, I have to leave my computer for a bit right now though!
read 1096 times
2/9/2009 4:51:31 PM (last edit: 2/9/2009 4:57:02 PM)
show user profile  Davesbeard
That sounds fantastic Toen! Thanks :)

I'm just having a play around with a PF Source now. Don't understand how to get the particles to collide in this either!

I've added a udynadeflector and a collision option into the event but i can't seem to add the deflector. Even when twinned with the test chamber. This is frustrating! Haha
read 1054 times
2/10/2009 5:32:32 AM (last edit: 2/10/2009 5:32:45 AM)
show user profile  Davesbeard
Ok i worked it out, Dyna deflectors don't work! Haha.

Managed to get my test chamber deflecting but i think because of the way i've modelled it particles are bouncing off nothing near the join between a tube and a half hollow sphere. I've just booleaned them together, is there a better way of merging objects?
read 1046 times
2/10/2009 6:02:14 AM (last edit: 2/10/2009 6:02:14 AM)
show user profile  Toen
Can you post image of how it's suppose to be setup?
read 1025 times
2/10/2009 8:51:29 AM (last edit: 2/10/2009 8:51:29 AM)
show user profile  Davesbeard
I've manged to get the Test Chamber set up properly, remodeled it and grouped the 3 pieces rather than booleaned them.

The link below is the basic concept of what i'm doing. Its not scaled like it will be, once i've got the real world units confirmed i'll be modeling the target, chamber and thruster appropriately.

For now the pink cylinder is the thruster, the cone like things are an example target and obviously the gray tube is the chamber. There is an exit aperture behind the target to simulate the exit to the cryo-pump. Basically i need to be able to count any particles that hit the deflector and then head back towards the thruster. Be it just after hitting the target or after passing through the target then bouncing off the chamber. Is there a way of counting particles passing through the tube with a component of velocity which is in the direction of the thruster?

Also, any tips on rendering this? I was just trying to get a video batch rendered to be able to simulate a reasonable amount of particles but no particles were showing up :/

Cheers for the help so far guys!
read 991 times
2/12/2009 7:11:48 AM (last edit: 2/12/2009 7:11:48 AM)
show user profile  Toen
Do you still need help with this Dave?
read 942 times
2/14/2009 8:09:10 PM (last edit: 2/14/2009 8:09:19 PM)
show user profile  Davesbeard
The help so far has been, absolutely brilliant. Cheers guys!

Your post especially Toen, really got me on the right track. I now have it set up that any particles who have hit the rear semi-sphere behind the thruster are sent to a third event (the second involving particles hitting the target) and i can count these using the method you suggested. I've not worked out how to get particles to stick to this rear semi-sphere though. How do i need to set up the deflector?

Also, is there a way of running the particle simulation and getting an output from the program with number counts for each event? Rather than just looking at the particle count in program?

Its no biggie, but it would be nice to be able to run the simulation (at the moment i'm just caching it then playing till the end..) and then have the particle counts in a notepad document or something. If this is tricky then its no biggie but it'll be worth doing if its easy!

Thanks again :)
read 883 times
2/19/2009 10:21:43 AM (last edit: 2/19/2009 10:21:43 AM)
show user profile  Dub.
I can write you a script to do this if you want.

You'd have to send through a max file so i can hook it in properly.

read 862 times
2/19/2009 1:15:51 PM (last edit: 2/19/2009 1:15:51 PM)
show user profile  Toen
"I've not worked out how to get particles to stick to this rear semi-sphere though. How do i need to set up the deflector?"

Filter those particles out with another pflow collision test set to that deflector representing the curved back end and in the collision test rollout in pflow, set the test to 'Collides' and it's 'Speed:' to 'Stop'. That will make the partcles stop on the deflector where they collide with it.
Then you can link that collistion test to a new event to do whatever you want with those particles like change their color, count them, etc like before.
read 845 times
2/19/2009 7:39:33 PM (last edit: 2/19/2009 7:40:04 PM)
show user profile  Toen
I just found this randomly while exploring around in PFlow.

In Particle View if you go to 'Options' then 'Track Update' and click on 'Particle Count' it will show you in a little tab above each event in Particle view how many particles are currently in that event ! lol
read 808 times
2/22/2009 1:05:01 AM (last edit: 2/22/2009 1:05:01 AM)
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