View Full Version : Particle question

07-28-2008, 11:48 AM
I need to make a mound of powder, such as you might see in a stock image of something powdery.

Right now, I'm trying to do it by piling up HV particles on top of each other, although even with size settings and interaction settings, they seem to clip through each other and lay flat on the ground. Is it possible to pile particles on top of each other?

If not, I'll have to model the mound and surface it. I don't have high hopes about that.

07-28-2008, 12:53 PM
Make sure you have the Self Interaction set to something other than NONE. Also make sure you have a Particle Size.

Over time the hill tends to continue to flatten out (unless you keep adding particles). I'd probably cheat (CG=Cheating Graphics) by adding a Cone that made the particles stick and animate that upward to get the cone. Probably use two particle groups so some would slide down the sides. Oh and surface the cone so it doesn't give way the trick.

07-28-2008, 12:56 PM
Oh and here's the scene (only took a minute to throw together).
Thanks to Aurora for teaching that online Particle class.
Makes this a lot easier to understand.

07-28-2008, 01:15 PM
Dang it, I tried all different choices for self interaction and interaction, and my particles had size, and they all stopped dead only at the ground plane.

I like the cone trick, though. I'll look at your scene.


07-28-2008, 03:20 PM
Another thought is to animate the surface of the cone so it looks like powder that is running down. Put animated displacement & bump on the surface too.
Probably could play with morphing that cone - but that will probably cause some dynamics issues.

Don't forget to make the cone a collision Object using stick.

07-28-2008, 04:36 PM
Oh, just a still image needed, not an animation!

Mr Rid
07-28-2008, 05:54 PM
LW calculation becomes impractical with 20,000+ self-interacting particles, which is nowhere near enough in my mind to sim a 'mound of powder.'

Sounds like something that would work better as mapped geometry, but how about just model a mound shape that is highly subdivided and apply HV to the vertices?

07-28-2008, 08:03 PM
Oh, just a still image needed, not an animation!

Now you tell me !!! :lol:

07-29-2008, 10:57 AM
Just surfacing. This might do it for me. I liked the HV idea, but I'm using radiosity on a slow machine here at work.


07-29-2008, 09:25 PM
OK... now share your scene so I can check out your surfacing.

07-30-2008, 12:23 PM
Okay, the scene is ever-evolving, but I think the powder hasn't changed from the previous post.

To give you an idea of how slow this computer is, I just interrupted this render from yesterday. 22+ hours. It was working on Segment 2 of 4, and estimated another 32 hours to go. And in my experience with radiosity and subsurface scattering, those predictions are usually WAY optimistic.

Anyway, my scene was designed to give the impression of a powder without showing a pile with lots of extra grains on the floor around it. It will be faded back behind foreground elements in an ad, too. But I know, as a graphic designer, the background elements can be just as important as anything in the foreground.

07-30-2008, 03:57 PM
Analyzing now....

07-30-2008, 05:21 PM
Rendering the scene, changed resolution to HDTV[1280x720]and that is all i changed,
time was ...
Preprocess=9.5 secs
GI time =15.2 secs
total time= 26 min 58 secs



07-30-2008, 06:02 PM
Damn you!

Damn you and your up-to-date equipment!

Looks like I need more DOF blurring to hide my cheesy, quick and dirty modeling.