View Full Version : Blowing snow over a surface

01 January 2008, 11:13 PM
I'm new here so hello everyone ! :)

What I got to do is a logo that is buried with snow. With the wind blowing, it slowly reveal what's beneath.

I'm not a advanced user with Max. I model and texture OK but I'm not very familiar with particle flow.

So what I'm looking for is the big picture... how am I going to achieve this. If you can provide links to some tutorials of technics involed in the process, it would be appreciate :)

Thanks all and glad to be on the board.

01 January 2008, 04:58 AM
What I got to do is a logo that is buried with snow. With the wind blowing, it slowly reveal what's beneath.
Don't you think it's better if you use a less sticky element than Snow for your project, something like sand, dust ... ?
Or Instead of using the wind to blow the snow to reveal the logo, why not melt the snow to reveal it?, Max's "Melt" modifier can give you some pretty decent results.
If you still want to stick with the particles, check Allan McKay's dispersion tutorial.
Hope this helps, and welcome to the forums :)

01 January 2008, 05:22 AM
Actually the snow is part of the concept/logo but thanks for the suggestions :)

The tutorial you pointed is pretty much what I want to achieve so thank you very much ! It's well explained and all. I think that will do it !

01 January 2008, 06:21 PM
Ok so did the tutorial and I think I understand the particle system. But my only problem now is that I'm searching how to assign a mesh as a deflector (if it can be done). Like I want the snow to avoid my logo...

Any idea guys ?

Edit: I've found that somes use UDeflector. I don't know why but I can't click on "pick object", it's greyed out.

01 January 2008, 07:53 PM
why but I can't click on "pick object",

First create UDeflector, then switch to the Modify brach, and only then define the reference mesh object. The option is not available during creation.

Oleg B.

01 January 2008, 08:06 PM
Yeah I figured that out just after posting... Thanks aynway. It's really appreciate.

01 January 2008, 07:57 PM
Ok I managed to do all the stuff that I wanted with the particle system. Now I'll begin working on the look of it. I would like some inputs of you guys, professional ;p

What do you suggest me to do to get pretty realistic snow (shape of particule, textures...). How would set up the scene ? (Just particles or I should use a kind a plane and just a part of particules?) Any hint is welcome.

Just to remember you, I got this logo burried that reveal itself with the wind blowing the snow.

You guys have been great so far so thank you all.

01 January 2008, 11:49 PM
I did this kind of setup a few times on "Day After Tomorrow." The MAX setup used PFlow to scatter stationary particles onto a surface in a controlled area (via poly selection or maps). These particles would live for a few seconds at a time (with variation). While they were alive they would Spawn a stream of particles that would be affected by forces. This would be the actual blowing snow part. I used a global directional wind to control the overal direction of the blowing, added simple collision geometry for the ground and nearby buildings (and boats), and then set the particles up to be shaded with low density Afterburn. That would be one pass. The second pass would hugely increase the particle count (via multiplier) and render as very tiny facing particles. This pass would render without AB (just as geometry) and then the two passes would be layered together in the comp so that the AB pass was a general volume pass and the facings would add detail. In certain shots where the lighting was more direct and less ambient, I added another pass of fewer particles rendered as small spinning cubes. These would have a very shiney material on them that would briefly catch light as they flew by the camera. This would add a sort of highlight pass to the effect and give you less of a steam look and more of a water/ice look.

Your mileage my vary; that was five years ago.

02 February 2008, 12:50 AM
Great tip with the cubes, BrandonD ;)

02 February 2008, 05:36 AM
Wow!Amazing.....just goes to show how much you can achieve with so simple an effect.....Love it Brandon:D .....

02 February 2008, 04:46 PM
If I were to do those same shots today with MAX I'd add FumeFX to the mix to create a generic velocity field to advect the particles through instead of any collision events.

02 February 2008, 06:09 AM
You mean, with the FFX follow, right? I'm having a project with a lot of snow/ice coming, I'm developing looks now :) Did you do some CG ice for the film too?

02 February 2008, 09:28 PM
Yeah, that's what I'm talking about - using FumeFX to create a velocity field that the snow particles can advect through. I've been finding this to be a very useful methodology to adding fluid motion to dumb particles. Keep in mind, the main motivation is when dealing with object interaction. If you're just creating snow blowing on a surface with nothing around, a fluid solver is a waste of time. However, if you've got debris in the way, a velocity field can give you very realistic fluid motion. The trick is blending the influence of the velocity field with the generic noise of the particles.

02 February 2008, 11:58 AM
Ok, I think I got it figured. Await some cool tests soon ;)

02 February 2008, 10:14 PM
Thank you all, that's all some great tips.

But since I pretty new let's get to the basics :P

I played a little bit with my settings, textures, but I can't achieve a good result. I want to know to make the ground in fact. Seems like if I only use particle, it will take A LOT to cover the entire ground (like 500 000+). What would you guys do ? Do I setup a ground with a texture and just some particle over it ? How could I make it look uniform ?

Actually, my particles look more like noise than anything. You don't feel at all the snow look. I used different texture with a "frequency maps" to random them... :/. I'm really far from want I want.

Any more tips left guys ? :)

02 February 2008, 08:47 PM
You need to build a shader for that, I guess lots of layered procedurals. And you can make the particles bigger, no need to spread lots of small ones. Make your shader, then animate the opacity and particle size as the freeze takes over. I am researching now, will post tests in a few days.

02 February 2008, 12:49 PM
I didn't even know that I could animate the size of the particles :/ ... I'll try tp play a little bit with this.

If you could post some tests it would be awsome ! Theres nothing like example :)

02 February 2008, 10:40 AM
Post some pics of what you have done, of your settings, of your scene of your material, your render tests. Come on. help us to help you.

You will get a LOT more replies if you overload us with info. I really WANT to help you, but like most people here, i dont have all day try to guess what you might be doing wrong.

You say nothing like example, then post your max scene, let us have a look at it to try and fix it.


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02 February 2008, 10:40 AM
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