Particle clumping technique

[Tim]

Hey guys, I'm looking for a way to emit a bunch of particles in clumps,
that over time break apart. Hopefully giving the impression of dirt
turning to a fine dust.

I'm imagining something like having a clump of 8 breaking into 2 sets of
4, then a few frames later having this turn into 4 sets of 2 and finally
8 individual particles.

I'm thinking of maybe using a clone point / add point as the base, and
finding a way of controlling the bunching from there. Although I'm keen
to hear if anyone has tried this and has any ideas.

Regards,

Tim

[Ben Beckett]

Hi Tim

Just wondering

Have you tried empolygonizer it work based of nulls. You could get 8 nulls and animate the appart and use this plugin to mesh.

Check out http://vimeo.com/9598332

Hope this helps even thought it a different way

Ben

elasticmonkeys.com

On 7 January 2013 09:40, Tim <tim_b...@hotmail.co.uk> wrote:

2 sets of 4

[Tim]

Thanks Ben, It might be an idea for some of the Hero ones, but I think ultimately there are going to be 10,000's emitted over a period of time. It's worth keeping in mind though.

Tim

[Rob Chapman]

Happy New Year!

10,000's then you will have to be careful with the clone points!. I
think a good scene to look at for this as an example WIP is the sample
scene that comes with SI - 'particle spell cast'. it has a setup
already made for cloning particles coming off the main points as well
as secondary friction / animation forces for these, might be a good
place to start for a basic setup.

best

Rob

[Tim]

Cheers Rob, just looking through the scene. The Spawn on trigger seems
like an interesting approach. At some random time my one particle spawns
two new ones with a slightly offset direction and with half the size of
parent particle. After a certain amount of time this process repeats.

Sounds like it should do the trick.

Regards,

Tim

[Vladimir Jankijevic]

Seems the message didn't get through! Here it is again:

Here is a bare bone scene I just built to give you a starting point. It basically assigns a groupID to the clumps and drives a partID attribute on the particles based on some criteria. You can then do whatever you want with that partID. Drive changes in direction and so on. Just take a look

Hope it helps

Vladimir

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---------------------------------------
Vladimir Jankijevic
Technical Direction

Elefant Studios AG
Lessingstrasse 15
CH-8002 Zürich

+41 44 500 48 20

www.elefantstudios.ch
---------------------------------------

[Tim]

That's exactly what I had in mind Vladimir! Thank you!

Regards,

Tim

[Sebastian Kowalski]

I've build something like that for the catrice spot last year (http://www.sekow.com/catrice_color), its a complicated tree. i could share an .emdl if you interested. just give me a sec to dig that one out.
sebastian

[Sandy Sutherland]

Sebastian I would also like to take a look at that - we have to do an effect of someone being hit by a projectile and disintegrating - in very little time and right now we have scaled down as we on last legs of Khumba so VFX people = ME as well as Rigging, Mocap etc... so not got a lot of time to R&D.

If possible - many thanks

Regards

Sandy

Sandy Sutherland | Technical Supervisor





________________________________________
From: softimag...@listproc.autodesk.com [softimag...@listproc.autodesk.com] on behalf of Sebastian Kowalski [li...@sekow.com]
Sent: 07 January 2013 12:42
To: soft...@listproc.autodesk.com
Subject: Re: Particle clumping technique

[olivier jeannel]

Hey Sebastian, I would also like to have a look if it is possible.
I'm doing completly unrelated things, but I'm just curious :D

Olivier

Le 07/01/2013 15:17, Sandy Sutherland a �crit :

[Tim Leydecker]

Hi Sandy,

I had the pleasure to get to use some nicely fractured and animated houses from Sebastian
and his collegues once, he�s really good at breaking things apart. I have no idea how they did it.

An alternative might be some Houdini inspiration, I am intrigued by this tutorial description:

http://www.cmivfx.com/tutorials/view/506/Houdini+Embers+And+Ash

Could be a start for what you need if Houdini is an option.


Cheers,


tim

[Rob Chapman]

it would be a better effect if each original particle lost mass & size
as it emitted smaller clones of itself. Not too hard to setup but
would be great to see - by the way Sebastian, I really love that the
dust on that commercial. - there is so many particles that it looks
like a fluid effect rendered with volume shader :)

best

Rob

On 7 January 2013 14:27, olivier jeannel <olivier...@noos.fr> wrote:
> Hey Sebastian, I would also like to have a look if it is possible.
> I'm doing completly unrelated things, but I'm just curious :D
>
> Olivier
>

[Sandy Sutherland]

Thanks Tim,

Houdini is not an option for now, but will look at that link for inspiration.

Thanks

S.

Sandy Sutherland | Technical Supervisor





________________________________________

From: softimag...@listproc.autodesk.com [softimag...@listproc.autodesk.com] on behalf of Tim Leydecker [baue...@gmx.de]
Sent: 07 January 2013 16:36

[Tim]

Hi Sebastian, that would be great! I saw that spot not that long a go
and the look of the particles were really something I was trying to
capture for this job, albeit a bit more smokey.

Regards,

Tim

[Sebastian Kowalski]

here you go, thats one of the first prototypes I've made.
the whole system evolved a bit after the catrice project (had to reuse it on an other job), but the essential idea seems not to differ from vladimirs solution. (hope thats true, didn't had a look yet ;) )
you need to set a custom id value to each member of a cluster of points (clump id).
in that case all clumps have the same amount of points.

in that scene file its just a drag force, dissolving the clumps. when you need some more forces you have to use the position average of every clump, and apply the needed force from that.
i am gonna share the more "sophisticated" scenes too, just need to comment them a bit.

i should say that the initial idea came from tim borgmann, I've just implemented it in an icy way ;)

take care
sebastian

[Tim Borgmann]

And I have to point out that I got my inspiration from an old project I did with Chris Keller. So I think it was rather Chris initial idea :)

Cheers
Tim

[Rob Chapman]

Sebastian, I never thought I would hear myself say this, but that is
some sexy dust! I see that you are not spawning or cloning anything
and the dust 'clump' with its own ID starts as is and its just the
gravity, drag and turbulence forces breaking it up. really nice
solution that works so well visually. It would be really hard to get
that look any other way - ie with 'hero' geometry shedding more
particles as they shrink as you would still be able to track the
emitting ones.

there are some good hints for getting certain types of better dust in
this scene you provided so I wanted to thank you for sharing. it
appears crazy amounts and very little transparency is the key here , a
kind of 'brute force' approach that I usually would not consider and
try to approach with a volume shader or with Exocortex's Slipstream.

thanks for sharing!

best

Rob

[Tim Borgmann]

Sebastian did a really fantastic job on this dust stuff! It's definitely
a (if not the) key element in the spot.
Cheers and thanks again to Sebastian
Tim

[Andy Moorer]

Looking at that scene now, this is nice work, and the result is lovely. Thanks for sharing, sparks a lot of ideas.

[Tim Bolland]

I agree with the other comments, thank you very much! This is like gold-dust to us ICE geeks (if you excuse the pun). Also great look dev by Tim Borgmaan too. Great job everyone involved.

Regards,

Tim

[Sandy Sutherland]

Thanks Sebastian - you are a star!

S.

Sandy Sutherland | Technical Supervisor





________________________________________

From: softimag...@listproc.autodesk.com [softimag...@listproc.autodesk.com] on behalf of Sebastian Kowalski [li...@sekow.com]

Sent: 07 January 2013 20:17

To: soft...@listproc.autodesk.com
Subject: Re: Particle clumping technique

[Thomas Volkmann]

Really cool stuff Sebastian!!

Just looked at it, and the 0,4,0 as mean value reminded me that I wanted to call someone in Hamburg :D Thanks for that, too!

Hope all is going well.

 

gruss aus Schweden,

Thomas

 

> Sebastian Kowalski <li...@sekow.com> hat am 7. Januar 2013 um 19:17 geschrieben:

> Am 07.01.2013 um 17:24 schrieb Tim <tim_b...@hotmail.co.uk>:
>

[olivier jeannel]

That's a super learning gift ! Thank's a lot for that :)
The result is just beautifull. I'm completly lost into the icetrees, but
what a lesson !
Would worth a tutorial somedays (with you speaking in the micro).

Excellent !

[Michael Heberlein]

Thanks Sebastian, that's interesting and looks very cool!

[Sebastian Kowalski]

really glad you guys like it, and yes, this only works with a huge amount of points.

the final spot had a lot of additional footage from after effects (particular) too, and the compositing of these two elements really sell the shots at the end.

sebastian

[Tim]

I'm just playing around with it now, and I'm wondering if there is a way
to generate clumps in simulation mode, and still get the forces to work
correctly? I have set it up so clumps are created every frame (which
works as expected) but It seems when I try to apply forces to this It
breaks the simulation completely and all the points disapear.

I'm not sure if I'm setting this up wrong, or it's a limitation with
this kind of set up. Basically I'm trying to get smokey dirt to fall
from a character over time.

I have attached an image to show how I structured the tree.


Regards,

Tim

[Ben Beckett]

Hi Vladimir

What does self.partID do am a little lost in the sim stack wondered if you had time to basically explain

nice job though

Thanks

Ben

[Tim]

Just a quick update, incase anyone else is trying to do something
similar. The culprit for the simulation forces was to do with the
ClumpSize attribute being used in the init force and velocity branch.
I'm not entirely sure why but if you re-define the attribute earlier in
the add points execution stack, it works (or at least the sim doesn't
break). Maybe it's something to do with context and what's defined, I'm
not sure. Now at least I am able to emit clumps over time.

Regards,

Tim

[Christian Keller]

What you could do to get some nice clumps ist emitting in a volume and eat the outer shell away with a fractal so you have a nice irregular shape.
Do this with several point clouds, that you have enough different pieces for the whole thing. (You could also do it in one point cloud but that's a bit more work.)
Then you could clone these pieces to your master point cloud. And parent them.
A nice way to get them falling apart is to precompute a gradient from the outside to the center on the base pieces. You could use this for the gradual dissolve from the shell to the center.


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christian keller
visual effects|direction

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f +49 40 386 835 33
chri...@me.com

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