animate snow in a box

[andreg]

Hi all,

 

I searched this forum for help on this one but found nothing of interest in relation to this job. I have to create a plexiglass box with animated snow flowing inside of it as if there was a snow storm in the box. This would be created using blower fans and fake snow or something.. we'll get there when the concept is approved.

 

For now I have to show them the idea with a 3d animation. I posted a quick test render using the blizzard particles and a few deflectors but I find that the snow needs to swirl a bit more and the box needs to be more "full". My question is, am I using the right particle system? I tried the vortex force to twirl the snow around but it only creates a kind of funnel and the particles remain in the center of the box. What would be the best approach to do this? render the particles or try to make this effect in AE?

 

thanks for the help!

 

I included a small video preview of the animation to show my progress

[Claudio Branch]

Hmm...your results look more like a popcorn machine than snow.

 

Perhaps Particular?

 

http://www.trapcode.com/

[andreg]

Thanks for your reply

 

to be honest I'd like to do it in 3D, this way I will learn how to control particles. Also this box is going to be part of a center piece for a tradeshow exhibit, so there will be objects all around the box and I don't want to be dealing with mattes and id's, because I will have to learn that too and I have time constraints (like everybody else:D).

 

Any other tips? I changed the particle to snowflakes now and added some motion blur, I will be posting an update of the progress done soon

[lecameleon]

Ok.. this is going to be slightly painful.. .

 

open up Max.. Make a box at origin (say, 300,300,300)... this is going to be your deflector.. not the model box you want.. you can model that separately once you are done with the snow sim...

 

Go to Particle Systems and add Particle Flow source into the scene.. Choose the Pflow Emitter Icon type as box and make sure it is the same size as the box you created.. (300x300x300) and align it so that the box and the pflow source are in the same location (align centres)

 

Now hit 6 on your keyboard... PFlow interface will open up.. Let the options remain at default for the present..

Delete the speed operator

These are the settings for your particle flow operators..

 

Birth: Emit Start 0 to Emit Stop 0 and Amount = 500 (say)

Position Icon : Set to Volume

Rotation : Random 3D

Shape : Tetra (or anything that pleases you, for now)

Display (Ticks)

 

Now select your (deflector) box and add a normal modifier to it to flip normals (I will tell you why you need to do this)

Now go to Space Warps and add a UDeflector in the scene.. you can place it anywhere..

In the UDeflector settings, choose the box as the deflector object

Leave the other values at their defaults/..

 

Add a Vortex in the scene at the center of the pflow icon.. make sure the vortex is pointing upwards.

Time On: 0 and Time Off to a large number (beyond your animation frame limit)

Under Capture and Motion settings.. Axial Drop 0, Damping 20

Orbital speed 1.5, damping at 20

Radial Pull 0, Damping 10

 

Add a wind to the scene so that the icon point to any one face of the box..

Then in the wind options...

Strength and Decay 0,

Wind Turbulence 5, frequency 3, Scale 0.5

 

Now press 6 (if the pflow interface is not already open, that is) and go to the Event 01 and right click.. append Operator > Force

Go to the force operator and add teh space warps by list.. add both the vortex and wind

 

Now in the same event append > Test > Collision.

Add the deflector UDelfector01 by list..

 

That should do for now.. play around with the various settings for vortex and wind to tune your animation.. nice sweeping snowflakes..

 

> Now you are left with the task of modeling the outer box which will be rendered as the actual display case... I leave that to you

 

See the attached files.. and happy particle flowing

 

EDIT: The reason we flipped the normals on the deflector was that if the deflector is applied directly the particles wont bounce.. it needs the normals to be facing the deflection side

Edited January 16, 2009 by lecameleon
Forgot to Explain:

[Peter M. Gruhn]

Whatever goes in the real box will be thin and light. Air resistance will keep them up. ... Your gravity is way too strong. There's a pulsing, that might be particle generation at frame boundaries. I think PF does sub-frame birth, don't know about Blizzard. Opening Max now... I hear you re: Vortex, but think we should be able to slow down that orbit/axials/etc to get motion with less funnel.

 

Hm.. it may not be gravity I'm seeing, it may be particle speed from the bounce. Since most of the speed comes from the fans, I'm going to add a wind (which I happen to know has some nice turbulence features) to try to blow things up. That will probably cluster them on the ceiling...

 

OK, not that bad. Wind speed way down. The pick up some speed I think from the turbulence so it gets pretty feisty in there. So I'm playing with the deflector bounce as a way to damp that. And that's even reasonable as in a closed system like that the wind will be still (or horizontal to) near the faces.

 

It's good to just put the thing on play and type in a number in a parameter and hit enter. type enter type enter type enter...

 

OK, I like this. They start a little weak, so I'll see about a negative start time... Good, don't forget to make the life longer.

 

Now, I was going to add a vortex to put some larger scale uniformity into the motion, but then I noticed the scale on the wind turbulence. Crank that down and the larger structures start to stick out. Even go a setting which piled up half the particles in the corner so they couldn't get out (which may happen to you in the real world. if you don't believe me, try spray painting the inside of a small box).

 

In order to safeguard against clustering, I'm just going to add a slow spin on the wind icon so maybe it sweeps the corners clear. Failed. To solve, I'm going to pick a turbulence setting that doesn't cause that. You may add a small gentle limited wind or vortex. You may pick a setting that doesn't cause that. (Frequency may help.)

 

[Why does it alway crash when a project is just about done?]

 

....

 

Right, the movie's done (avi) - snowbox02.zip

And a stripped down version of the model - snowbox alone.max.zip

 

Should be something to get you started.

[lecameleon]

That's pretty neat.. .good one..

 

On a more practical note... I was wondering if you could maybe achieve this effect with little thermocol particles and a weak electrostatic force generated on the roof of the box with just about enough attraction to hold the particles in mid air and then use some smaller wind turbulence to create the chaos... That way you would not need to use large wind sources or fans...

 

oh.. or even better.. use a moving electrostatic field on the roof so that the particles collide among themselves and then you wouldnt even need to use wind..

 

I suppose that is getting a bit too far-fetched..

 

Anyways... good animation above.. bent towards the realistic sim than the one I provided above..

[andreg]

Thanks for the help and for the files! Since the design changed to a box with windows, instead of a transparent cube, I will be using an animation clip of snow in the diffuse channel of my window openings. The effect is good enough to show the idea without using and rendering particles. But I will keep the file you sent me for future reference if the need for something like this arises again.

 

Thanks for your replies!