Stop Moving Particles Within A Field?

[stingray2005]

How could I stop particles moving, if they are entering any volume-field?

I will show particles flowing through a pipeline - on some places in the pipeline some of the particles should be caught by a field. The particles, which are influenced by the field, shouldnt move inside the field to, ae the pivot point of the field or so - they only should stop moving.

I hope you know what i want, my english is far from perfect

(The particles are part of a curve flow function)

thanks for suggestions!

[david-schoneveld]

play with volume exclusion option turned on, on your fields. might be of some help.

[stingray2005]

thanks, but that wont work with particles along a "curve flow".
the "drag" field, or any other, wont influenced the particles.

heeelp!!

[stingray2005]

Its really important for me, to get this work the next hours

Please send me any suggestions, how i can solve this problem!!

thanks again !

[joojaa]

Oakay fisrt you mnust understand that ALL movement in a curve flow happens within a EXPRESSION. And as such the expression uses particle goals to controll the flow NOW the goal will still affact the object no matter what happens. Secondly you should be a avare that curve flow is, like all other things in the effects menu, a example.

BUt you can certaily do fix this, in many ways, but it will rrequire you to modify the expression in some way, its a bit triky tough since you need to modify the curve flow.

NOw teh particle goal is set to the goal offset attribute that does eventually prevail without taking into consideration 1 frame dynamics. Now inorder for you to get maya to relaease its grasp of the flow you need to release particles form the curve in some way.

easisst is to set goal pp to 0 at asome stage for example the goalPP could be set to realease the goal gradualy in mid flight with 1- 1linstep(0.5 ,0.6 ,Flow_particleShape.ageNormalized), you coul

[stingray2005]

thanks for your suggestion!

the big problem is, that i haven't any expirience with expressions. maybe somebody out there have a example, from which i could learn??

or an expression-solution for my problem?? (1. Particles should stop if they are inside a field)

thanks for suggestions!

[david-schoneveld]

well it's very hard to write an expression on the condition that a particle is or isn't inside a field, not impossible but not simple. You want particles to stop once inside a field. I don't understand why you want that. whats the point of them being inside a field if all they are doing is stopping? Why not just make an invisable collision object or something.

have you tryed a drag field set to volume with high magnitude? that stops particles dead.

if you want a boundry of drag for happen before the particles get into an other field make 2 drag fields one exclusion that's smaller, one bigger normal volume field, then your regular field inside.the smaller one.

[stingray2005]

Thanks - a step further

The collide object stops the particles flowing along the curve (Z direction), but they still moving in X & Y randomly.

Do you know an expression, if particles collide, stop moving?? thanks again!

[david-schoneveld]

yeah, collision event the kills the original particle and births a new on that doesn't inharet the velocity

[ev1an]

Hello! I have a very similar problem, however the particles should continue moving again after a certain time....

I'm working on an architectural project dealing with digital design methods.
For this, i would need to simulate the traffic and the movement of a site, which then could be used further in the design process by abstracting it using fields etc. I started with creating several curve flows for each direction, which works pretty well.

However i would like to add the effect of traffic lights, or to better say to stop the curve flow for a moment on a certain spot and then to let it run again a bit later - considering that the particles which have passed the "traffic light" at that moment would continue moving.. (I guess you get it)

I tried to solve this by inserting a passive rigid body (nurbs plane) where the traffic light should be and make the particles collide with it - actually it works pretty fine as it has exactly the effect i want and makes the particles stop, apart from the fact that the particles (render type spheres) collide together into a bunch which is not very realistic if you imagine they were cars.. what i would like to is the first particle that reaches the plane to stop (which happens) but then the next particle to stop behind it without crashing into it.. Hope this makes sense!
Now i tried to solve that by adding a radial field to the single particles in order to keep them away from eachother but i think i either dont get the right settings or it doesnt work that way at all.. actually exactly nothing happens.. I used the settings from Learning Maya Dynamics - Chapter Particle Instancing where it's described how to keep particles away from eachother, however that was in another context without collisions obviously..

does anyone know how to achieve this in a smart way? :-p

thx
evian

p.s.

QUOTE
The collide object stops the particles flowing along the curve (Z direction), but they still moving in X & Y randomly.

I'm really not an expert with particles, but i think just by setting the resilience to 0 and friction to 1 in the geo-connector node of your particle object, you will stop the particles completely (that's the method i used).

[stingray2005]

thanks, somtimes the solution is quite easy

the main problem isnt solved, but it works for me

(PS: Main problem --> A field, where particles, which are in sew of it, would be directed to the pivot point of the field --> then they collide in the field with a invisible poly object --> if so, they would die & emit a "stopped" particle. hope you get it!)

thanks again for your great help!